Heat oven to 375°F. Prepare an 8x8" baking pan by lining it with parchment paper. Set aside.
Drain and rinse a 19 ounce can of chickpeas, reserving the aquafaba for another use, if desired.
Add the rinsed chickpeas to the bowl of a food processor, along with 3/4 cup lightly packed brown sugar, 1 large egg, 2 Tablespoons canola oil, 2 Tablespoons cornstarch, 1 Tablespoon vanilla, 1 teaspoon baking powder, and 1/2 teaspoon kosher salt. Process until smooth. Stir 3/4 cup chocolate chips.
Pour the batter into the prepared baking pan, smoothing it into the corners with a spatula. Sprinkle the top of the batter with up to 1/4 cup additional chocolate chips, if desired.
Bake for 35-45 minutes, until the top is completely set, the edges are beginning to brown, and a toothpick inserted into the center comes out with a few crumbs clinging to it. Cool for at least 30 minutes on a wire rack before cutting.
Cut into 16 squares, and serve warm or at room temperature. Store leftovers in an airtight container or zipper bag at room temperature for up to 2 days, or in the freezer for an extended period of time.