Easy Blueberry Blondies Recipe (with Crumble Topping)

Why You Will Love This Recipe

This recipe is easy to love because:

1. It is bursting with fresh blueberries. It is truly a blueberry overload in flavor. It is sweet and slightly tart, with a burst of juiciness that brings a refreshing, fruity note.
2. A deliciously perfect breakfast treat - or after dinner dessert! It pairs wonderfully well with coffee or tea. 
3. Easy to make! Only a few ingredients are needed, and it comes together in about 1 hour from start to finish! There is a rough waiting period because we need to wait until it has completely cooled down, but I promise it is worth the wait. 

If you are looking for other fruit-inspired desserts, then I recommend also trying my Strawberry Sugar Cookie recipe, Berry Cake, or Banana Bread Cookies! Or if you want to try other blueberry recipes then I recommend my Blueberry Lemon Cookies or Cake Mix Blueberry Muffins that are also bursting with juicy blueberries!

Ingredients

Please read through the ingredients list so you can familiarize yourself with each ingredient, along with suggestions or recommendations during the preparation or baking process. Please see the Recipe Card for all details.

Blueberries. The star of the show! I recommend using fresh blueberries because I found they are easier to work with, and I would avoid frozen if you can. If you are in a bind, you can substitute with frozen blueberries.

Brown Sugar. You can use either dark brown sugar or light brown sugar. Both work well. 

Butter. I use unsalted butter, but you can use salted butter. If you use salted simply omit the added salt in the recipe. 

Old Fashioned Oats. Not to be confused with instant oats! This will be part of the crumble and help add a wonderful chewy texture to the blueberry crumble blondies.

Pre-Bake Tips

Use Kitchen Scale. The greatest advantage you can give yourself when baking is using a kitchen scale. It helps more accurately measure ingredients by weight vs. volume.

Spoon and Level Flour. If you do not have a kitchen scale, then spoon and level your flour to ensure you are not adding too much. 

Room Temperature Ingredients. Make sure your butter is softened before beginning.

Wash and dry the blueberries well before you begin. 

Variations

• If you are a blueberry lemon lover, then I recommend substituting the vanilla extract for lemon extract to create lemon blueberry blondies. You can also add lemon zest to the sugar for the crumble, and rub the sugar and zest between your fingers to help release the lemon oils. 
•  Spruce up the recipe with white chocolate blueberry blondies by adding white chocolate chips or chopped white chocolate! You can also melt the white chocolate and drizzle over the blondies when cooled. 
• Help that crumble shine even further by dusting lightly with confectioners' sugar! Use a sifter to gently add a light layer of powdered sugar to the top of the blondies, or a lemon glaze. 
• Craving raspberries instead of blueberries? I don't blame you! Easily substitute the blueberries for raspberries to make raspberry blondies! 

How To Make These Easy Blueberry Blondies

This Easy Blueberry Blondies Recipe with crumble topping uses baking tools and ingredients that can be found in most homes. Please see the recipe card for a full list of equipment and ingredients.

Step 1: Preheat oven to 375 F. Combine flour, baking powder, and fine sea salt in a bowl and whisk well. Set aside. 

Step 2: Melt butter in a microwave-safe bowl and microwave until melted. Add brown sugar and whisk well - about 1-2 minutes.

Step 3: Add egg and vanilla and whisk until well combined, about 1 minute.

Step 4: Add dry ingredients to wet ingredients, and use a rubber spatula to fold until just combined. 

Hot Tip! Folding uses a scooping method to help combine ingredients without releasing too many air bubbles. Use a rubber spatula to cut through to the bottom and then lift from the bottom to fold over. Continue until the dry ingredients are mostly combined.

Step 5: Add blueberries and fold in until evenly dispersed. Do not overmix. Stop folding once the blueberries are evenly spread throughout, about 3 to 4 folds in.

Step 6: Prepare an 8x8 square baking pan with parchment paper (for easy removal after baking). Place blueberry blondie batter into a baking pan and use an offset spatula to spread evenly.

Step 7: In a separate bowl, combine all the crumble top ingredients except for the melted butter. Mix well for even distribution.

Step 8: Add melted butter to crumble dry ingredients and use a spoon or fork to mix evenly. 

Step 9: Sprinkle crumble topping on top of the blueberry blondie batter.

Step 10: Bake for 37 - 40 minutes. Remove from oven and place on cooling rack. Make sure to cool completely before cutting.

FAQ's

Storage

Post Bake Storage. This recipe is best enjoyed within a day or two after baking. I recommend placing them in an airtight container, not layered on top of each other and left at room temperature. You can also place it in the refrigerator for up to 5 days.