Heat the oven to 325°F (163°C). Lightly grease a 5×5-inch baking dish and line it with two overlapping sheets of parchment paper, leaving overhang on two sides.
Add the egg, almond butter, brown sugar, maple syrup, cocoa powder, oil or melted butter, vanilla, salt, baking soda, and 2 tablespoons of water to a bowl. Stir until smooth and combined.
Fold in the chocolate pieces or chips until evenly distributed.
Scrape the batter into the prepared baking dish and spread into an even layer.
Bake for 25 to 30 minutes, until the top is puffed and a toothpick inserted in the center comes out with a few moist crumbs attached.
Use the parchment overhang to lift the brownies onto a cutting board. Cool for at least 10 minutes before slicing into squares.
Notes
Stir your almond butter before measuring. Almond butter separates in the jar over time. If the top is oily and the bottom is dry and stiff, the measurement will be off and the brownies won't hold together. Give it a thorough stir before scooping. This applies to peanut butter and sunflower seed butter too.Pull them out at moist crumbs. This is the most important step. Flourless brownies should never bake to a clean toothpick. Moist crumbs on the pick mean fudgy brownies. A clean toothpick means they've overbaked and will be dry. Start checking at 25 minutes.Let them cool completely before slicing. Flourless chocolate brownies come out of the oven feeling very soft. That's normal. They firm up as they cool. Give them at least 10 minutes on the cutting board. Cut too early and they'll fall apart.Line the pan with parchment paper. Grease the 5×5-inch baking dish first, then lay two overlapping sheets of parchment with overhang on two sides. The grease holds the paper in place, and the overhang lets you lift the whole slab out for cleaner slicing. Without parchment, flourless brownies can stick because there's no flour to create a dry surface against the pan.If doubling the recipe, double the ingredients and bake in either two 5x5 inch baking dishes or one 6x8 inch baking dish.