Line a 9-inch x 5-inch loaf pan with parchment paper. Set aside.
In a food processor with the S blade attachment, add all the ingredients: peanut butter, maple syrup, almond milk (make sure the almond milk is at room temperature. If just out of the fridge, it solidifies the peanut butter and won't come out as good), unsweetened cocoa powder, flaxseed meal, and coconut flour.
Process on medium speed until all the ingredients come together and form a consistent brownie batter. It shouldn't take more than 30 seconds. The dough will be dark, sticky, and thick. That is what you want. If it looks very dry, which can happen if you did not measure the flour precisely, add 1 extra tablespoon of almond milk. Process again.
Gather the brownie batter with your hands. It is sticky, so you can wet your hands to make this easier. Transfer the no-bake brownie batter onto the prepared loaf pan and press to flatten using a silicone spatula. Freeze for 5-10 minutes. Meanwhile, prepare the frosting.
Chocolate peanut butter frosting
In a small mixing bowl, combine peanut butter, maple syrup, and unsweetened cocoa powder.
Remove the brownie from the freezer and spread the chocolate frosting on top. Note that the frosting will stay shiny and sticky. It won't solidify, it is a soft creamy topping.
Place the no-bake brownie in the fridge for 1 hour before slicing. This will give the flavors time to combine, and the texture will be perfect.
Cut into 8 squares.
Store in an airtight container in the fridge for up to 2 weeks.
Nutrition panel for keto, using sugar-free monk fruit syrup. Note that the texture will vary using sugar-free syrup. Calories: 162 kcal, Fat: 10.9g, Sugar: 2.7g, Carbs: 14.6g, Fiber: 6.9g, Net carbs:7.7g Protein: 6.5g