Introduction: Blueberry Crumb Bars (Indigo)

These blueberry crumb bars are a frequent request in my household. My family can go through an entire tray in a single day, and it's no surprise given how tasty they are. The blueberry filling has the perfect amount of sweetness with a little hint of lemon, and the crumb complements it perfectly; light, sweet, and buttery. So what are you waiting for? Follow this instructable to make these blueberry crumb bars. I promise you that you won't be disappointed!


  • 1 9x13 pan
  • Butter, for greasing the pan

For the Blueberry Filling:

  • 4 cups fresh blueberries
  • 1/2 cup granulated sugar
  • 4 teaspoons cornstarch
  • 3 tablespoons lemon juice

For the Crumb:

  • 3 cups flour
  • 1 cup granulated sugar
  • 1 teaspoon baking powder
  • 1 cup (2 sticks) cold butter
  • 1 egg
  • A pinch of salt


  • 1 tablespoon blue food coloring
  • 3 drops red food coloring

Step 1: Prep Work

Preheat the oven to 375 degrees F. Butter a 9x13 inch pan.

Step 2: Make the Blueberry Filling

In a medium sized bowl, combine the sugar, cornstarch, and lemon juice. Rinse the blueberries and add to the bowl. They should be wet enough to ensure the mixture covering the blueberries becomes a thick, viscous liquid. Fold blueberries in gently. Set aside.

Step 3: Make the Crumb

In a large bowl, whisk together the flour, sugar, baking powder, and salt. Once combined, cut the butter into small cubes and add to the dry ingredients. Using your hands, mix the butter in until there are only small pieces remaining and a crumbly dough has formed. Beat the egg, then add to the dough. OPTIONAL: If you want to give your crumb a fun light indigo tint, add the food coloring to the egg and mix before adding to the dough.

Step 4: Blueberry Bars... Assemble

Press slightly more than half of the dough into the prepared pan in an even layer. Give the blueberry mixture a quick stir to cover all of the blueberries, then pour over the crumb and spread evenly. Sprinkle remaining crumb over the blueberries and pat down gently. Bake for 45-50 minutes until top is golden brown. Let cool 15-20 minutes before slicing into squares and serving. Enjoy!

Optional: If you want to make your bars even more indigo, mix blue and red food coloring with a couple teaspoons of water until you reach your desired shade. Brush gently over the top of the bars once cooled.

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