Preheat oven to 325ºF and line a large baking sheet with silicone liners or parchment paper. Use two sheets if your pans are smaller – you don’t want to crowd the cookies.
In a large bowl, beat together the peanut butter and butter until creamy. Beat in sweetener, and then beat in the egg and vanilla until well combined.
Add the almond flour, peanut flour, baking soda, and salt and beat until the dough comes together.
Form the dough into 1 inch balls and place about 2 inches apart on the prepared baking sheet. Press down with the palm of your hand to about ½ inch thick.
Bake 12 to 15 minutes, until soft and puffy, and just barely browned. Remove from the oven and use the back of a rounded teaspoon to form a well in the center of each cookie. Let cool completely.
Chocolate center
In a microwave safe bowl, melt the chocolate chips and peanut butter together in 30 second increments, stirring until smooth.
Use a small spoon to dollop the chocolate in the wells of the cookies. Refrigerate until firm, about 30 minutes.