Preheat oven to 350°F. Grease or line an 8x8-inch baking pan.
Blend together almond flour, cocoa powder, salt, baking powder, butter, eggs, sweetener, vanilla extract, and xanthan gum in a medium mixing bowl just until combined.
Set aside ⅓ cup of the brownie batter. Stir in chocolate and peanut butter chips. Spread evenly in prepared pan.
Spoon small scoops of the reserved brownie batter and peanut butter over the top. Swirl the brownie batter and peanut butter together with a butter knife. Sprinkle on additional baking chips on the top, if desired.
Bake 20 to 25 minutes or until desired doneness has been reached.
Allow brownie bites to cool in pan on rack for 10 to 15 minutes then remove from pan and cool completely. Cut into squares.
If you don't have peanut butter chips, you can just add a bit more peanut butter to maintain the flavor.The brownies can keep fresh for up to a week or a week and a half when you store them in a container that is airtight. If you keep that container of brownies in the fridge, they can even last up to two weeks. They freeze well too!