Position a rack at the lower third of the oven and preheat to 350*F. Line a 9 x 9-inch baking pan with parchment paper and set aside.
Add butter, sweetener and peanut butter into a large bowl and whisk until thoroughly combined. It may be quite thick.
Add one egg at a time, whisking well after each one util it's completely incorporated. The texture should be smooth (except for any peanut chunks), with the sweetener dissolved. Whisk in the vanilla extract.
Add the almond flour, salt and baking powder, and whisk vigorously until fully blended. The mixture will be thick. Fold in the chocolate chips, transfer the batter into the prepared baking pan, and top off with extra chocolate chips and flacked sea salt. If you're using salted peanut butter, you will want to take care not to over salt.
Bake for about 25 minutes until the center is just set. Begin checking doneness at about 20 minutes. Do not over bake, and remember there will be additional carry-over baking once removed from the oven.
Cool completely on a wire rack before attempting to remove the blondies from the pan. When ready, lift blondies up and out of the pan using the edges of the parchment paper. Cut into desired size (or shapes!).
Store in an airtight container for up to five days, or in the freezer for up to one month.