Preheat oven to 350° F / 175° C. Lightly butter an 8×8-inch square baking tin, line with parchment, and set aside.

Melt butter in a saucepan over medium heat. When butter has melted, stir in sugar, cocoa powder, and salt. Remove from heat and let cool slightly, about five minutes.

Transfer butter-sugar-cocoa mixture to a large mixing bowl.

Add egg, vanilla bean paste, and almond extract to butter-sugar-cocoa mixture, and stir to combine.

Fold in flour and baking powder, followed by canola oil.

Fold chopped chocolate and almonds into the batter, followed by chopped Italian rainbow cookies, stirring until just combined. Pour batter into prepared tin. (Mixture will be thick).

Top batter with additional slices of Italian rainbow cookie. Use your fingers or a spatula to press evenly into the tin.

Bake in preheated oven for 30 minutes, or until a cake tester comes out clean.

Transfer brownies to a wire rack and allow to cool completely, at least one hour.

In the microwave or the top of a double boiler, melt 2-3 tablespoons dark chocolate. Transfer to a piping bag and drizzle melted chocolate evenly over the top of the brownies.

Slice brownies and enjoy. Store leftovers in an airtight container at room temperature for up to five days.