Step 1

Preheat oven to 350°F. Line an 8×8-inch pan with parchment paper or foil and grease lightly.

Step 2

In a medium bowl, toss together raspberries and tapioca starch. Let stand while you prepare the crust.

Step 3

In large bowl, combine the rest of the ingredients except the chocolate chunks. Stir until combined.

Step 4

Reserve 1 cup of crumb mixture for the topping. Press remaining crumb mixture evenly into the bottom of greased pan. Bake at 350°F for 10 minutes.

Step 5

Remove partially baked crust from the oven. Sprinkle chocolate over the crust. Evenly distribute raspberries on top. Top with remaining crumb mixture.

Step 6

Return to oven and bake for another 30-35 minutes or until bubbling and lightly browned. Let cool completely before cutting into 16 squares.