In a mixing bowl, combine the peanut butter, egg, cocoa powder, and a pinch of salt. If you prefer a sweeter taste, add monk fruit sweetener according to your preference. Mix until smooth, incorporating one tablespoon of chocolate chips. If the batter is too thick, gradually mix in water.

Plug in your mini waffle maker and preheat it according to the manufacturer's instructions. Coat the plates with non-stick spray to prevent sticking.

Once the waffle maker is preheated, pour half of the batter onto the center of the plates. Sprinkle half of the remaining chocolate chips over the batter. Close the lid and cook for about 2-3 minutes, or until the steam reduces significantly.

Carefully open the waffle maker and use a fork or spatula to lift out your Brownie Waffle. Let it cool slightly on a wire rack. Repeat with the remaining batter and chocolate chips.

Serve warm and top with butter or drizzle with sugar-free maple syrup. Optionally add whipped cream or keto ice cream.