These easy peach raspberry oatmeal crumble bars use one buttery brown sugar dough for the crust and oat crumble, with fresh summer peaches and raspberries layered in between. Like a pie but far less work, these crumb bars are great to take to a picnic or barbecue since they can be served cold or warm – ideally with a scoop of vanilla ice cream! Recipe is designed for an 8″x8″ square pan but can be doubled in a 9″x13″ pan if you need to feed a crowd.
Why you’ll love this recipe
One more summer dessert recipe for you! There are several reasons why I love making crumble bars instead of a full crisp or pie, and it all comes down to ease, versatility, and portability. Particularly in late summer when time feels short and fall approaches, I want recipes that are fast, easy, and make the most of summer produce so I can get back to being outside!
These peach raspberry bars:
- have all the nutty, buttery, brown sugary flavor of a fruit crisp, pie, or crumble at a fraction of the time and effort.
- can be picked up and held by kids and adults,
- can be easily cut and transported without a big mess,
- can be eaten warm or cold,
- are allergy-friendly: they are egg-free and easily made gluten-free or vegan (see substitutions section of this post); and
- can be topped with ice cream for dessert, peanut butter or almond butter for an afternoon snack, or nothing at all for …any time.
Furthermore…did I mention that we only need ONE DOUGH (and one bowl) for the crust and the crumble topping, and no mixer is required?
Only a few simple ingredients needed for these peach raspberry oatmeal crumble bars, and you can substitute or customize as noted below to make these your own! See the recipe card at the bottom of this post for full ingredient list and measurements.
For the brown sugar oat crust base and crumble topping:
- Old-fashioned oats (also known as rolled oats; use certified gluten-free oats if needed)
- All-purpose flour (or an equal amount of gluten-free all-purpose flour mix with xanthan gum like Bob’s Red Mill 1:1)
- Brown sugar (can substitute coconut sugar, granulated sugar, or another granulated sweetener)
- Unsalted butter (can substitute coconut oil or vegan butter)
- Vanilla extract
For the peach raspberry filling:
- Fresh peaches (about 1 cup chopped; you’ll need 1-2 peaches and there’s no need to peel them!)
- Fresh raspberries (about 1 cup)
- Corn starch or arrowroot starch
- Granulated sugar (only a little bit, and you can substitute coconut sugar or any granulated sweetener)
- Lemon zest (optional but delicious)
- Large bowl – I like to use a big glass microwave-safe bowl so I can melt the butter in it – one bowl recipes for life!
- 2-cup glass measuring cup or bowl (for measuring and mixing the fruit filling)
- Whisk (or fork) and rubber spatula
- Kitchen scale – I highly recommend weighing your ingredients for most accurate results, especially the flour! This is the primary way I bake these days as it is much more precise than using measuring cups (and there are less dishes to clean).
- Microplane zester (not strictly necessary but…makes your life a whole lot easier when zesting the lemon)
- 8″x8″ square baking pan (I think 9″x9″ would make the bars too thin)
How to make peach raspberry oatmeal crumble bars: Step by Step
Like many of my recipes, the method here is streamlined and simple. No mixer and only one bowl needed! See the recipe card at the bottom of this post for full instructions.
- Prepare the pan: Preheat your oven to 350 degrees F. Line an 8×8 inch square pan with parchment paper (easiest method to get the bars out) or grease the pan well, and set aside.
- Chop the fruit: wash the fruit, then dice the peaches (no need to peel them) into chunks about the size of your raspberries. You can tear the raspberries into pieces if they’re large but it’s likely not necessary. You’ll need about a cup of each fruit. I like to place them in a large Pyrex measuring cup as I’m chopping so I can see how much more I need, but a medium bowl works well too.
- Mix your raspberry peach filling: add sugar, corn starch or arrowroot starch, and lemon zest (if using) and mix it all together. Set fruit mixture aside.
- Make the crust and crumble mixture: in a large glass bowl, melt the butter in the microwave in 15 second increments (or melt it on the stove). Whisk in the brown sugar, cinnamon, salt, and vanilla, then add the dry ingredients (oats and flour) and stir until well combined.
- Assemble the bars: Set aside 1/3 of the crumble mixture; pour the other 2/3 into the bottom of the pan and press into a flat even layer with your hands. Add the peach raspberry mixture on top; there shouldn’t be a tremendous amount of excess liquid but if there is, don’t include it so the bars don’t get soggy. Sprinkle the remaining oat crumble mixture evenly on top of the fruit.
- Bake for 35-37 minutes until golden brown. Fruit may be bubbling or not; it’s ok either way! LET COOL COMPLETELY IN THE PAN (I put it in the fridge to help it along) before lifting the parchment paper from the pan to remove the bars, otherwise they will fall apart. Cut into bars and serve warm or cold!
For best results on these peach raspberry oatmeal bars:
- CHILL BARS COMPLETELY before cutting them. Trust me on this – unless you’re planning to dig in directly with a spoon (good on you), you’ll want to wait until the bars are completely cool and ideally chilled before cutting them. Otherwise, they WILL fall apart on you.
- Cut the peaches to be about the same size as the raspberries – that way the bars turn out evenly mixed. Sweet juicy peaches + tart raspberries = the perfect combination of flavors.
- Ideally use fresh peaches and fresh raspberries, but you can use frozen fruit in a pinch – see the substitutions section of this post.
Room temperature: these peach raspberry crumble bars keep for up to 2 days at room temperature, although they will be quite soft. Once cut into bars, they are great for transporting to parties! I recommend keeping them in the fridge for best texture though.
Refrigerator: Bars will keep, covered in an airtight container in the fridge, for up to 5 days. Reheat in the microwave before serving, or serve cold, whatever you prefer.
Freezer: the oatmeal bars can be frozen, well-wrapped in plastic wrap and stored in a freezer bag, for up to 3 months. Thaw at room temperature for 2 hours or overnight in the refrigerator before serving, or simply reheat in a 350 oven for 10-15 minutes or in the microwave for 30 seconds. I like to freeze individual servings of these crumb bars so I can have them any time of year.
Additions and Substitutions
Here are some options to customize the recipe and make it your own:
- Lemon Glaze: to make the peach raspberry oat bars look pretty, you could add a simple lemon glaze: mix 1/2 cup (56g) powdered or confectioner’s sugar with 1 Tablespoon of lemon juice, and drizzle over top of the cooled bars.
- Different Fruit: you could try blackberries or blueberries instead of raspberries; plums, nectarines, or apricots instead of peaches; any summer fruit will work here as long as you stick to about 2 cups (475 ml) of chopped fruit in the filling!
- Double the recipe: use a 9×13″ pan and double all of the ingredients. Bake time is the same!
- Use only peaches or only raspberries: totally fine to do this if you don’t have both fruits on hand! Peach crumb bars or raspberry crumb bars both sound amazing on their own. Use 2 cups chopped fruit of choice.
- Make it gluten-free: you can use a gluten-free all-purpose flour mix in place of the all-purpose flour, or grind more oats in a blender into 1 cup (92g) of oat flour to use instead of the all-purpose flour.
- Make it vegan: use melted coconut oil or melted vegan butter in place of the melted butter.
- Oats: you can use quick oats instead of old fashioned oats, but do NOT use steel cut oats in this recipe – their texture will not work here.
- Frozen fruit: you CAN use frozen peaches and frozen raspberries instead of fresh fruit here, and you do not need to defrost them first unless the peach slices are very large. In that case, I would recommend thawing and chopping the peaches before using in the recipe so all of the fruit cooks evenly.
More Summer Fruit Recipes:
- Strawberry Oatmeal Crumble Bars
- Summer Stone Fruit Crisp
- Blueberry Crisp
- Simple Peach Cobbler
- Peach Almond Galette
Peach Raspberry Oatmeal Crumble Bars
- 1 large mixing bowl
- 1 2-cup (475 ml) glass measuring cup
- 1 kitchen scale (optional but recommended)
- 1 microplane zester (optional but recommended)
- 1 8×8 inch square pan
For the peach raspberry filling:
- 1 cup (170g) chopped peaches (about 1 fresh peach; no need to peel)
- 1 cup (120g) raspberries (no need to chop unless they're large)
- 2 Tablespoons (24g) granulated sugar
- 2 teaspoons (5g) cornstarch (or arrowroot starch)
- Zest of one lemon (approximately one Tablespoon) (optional)
For the crust and oat crumble:
- 1/2 cup (113g) unsalted butter
- 1/2 cup (100g) brown sugar
- 1/2 teaspoon vanilla extract
- 1/2 teaspoon cinnamon
- 1/4 teaspoon salt
- 1 cup (90g) old-fashioned oats
- 1 cup (125g) all-purpose flour
- Preheat your oven to 350 degrees F. Line an 8×8 inch square pan with parchment paper or grease the pan well, and set aside.
For the peach raspberry filling:
- Chop the peaches into bite size pieces (no need to peel). Layer with the raspberries in a 2-cup (475 ml) glass measuring cup like a Pyrex, or a medium bowl – you should have about a cup of each fruit, but it doesn't need to be exact.
- In the measuring cup or bowl, toss the peaches and raspberries with the sugar, lemon zest, and corn starch or arrowroot starch until fruit is completely and evenly coated. Set aside.
For the crust and oat crumble:
- In a large microwave-safe bowl, melt the butter in 15 second increments (or melt butter on the stove if desired). Whisk in the brown sugar, vanilla, cinnamon, and salt until well combined. Add the flour and oats to the bowl, and stir with a spatula until it's a well-mixed crumble mixture.
Assemble the bars:
- Set aside 1/3 of the oat crumble mixture; pour the other 2/3 into the prepared pan and press into a flat even layer with your hands.
- Pour the fruit mixture evenly over the crust layer. There shouldn't be excess liquid with the fruit but if there is, leave it behind.
- Sprinkle the remaining 1/3 crumble mixture over top of the fruit as evenly as you can, but this isn't an exact science. Just make sure it all gets on top.
- Bake for 35-37 minutes, until crumble and crust are golden and fruit may be bubbling, but it doesn't have to be. LET COOL COMPLETELY IN THE PAN (I often put it in the fridge to help it along) before lifting the parchment paper from the pan to remove the bars, otherwise they will fall apart.
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