Grease or line with parchment paper the bottom and sides of an 8x8-inch baking pan. Set aside.
Add butter, sweetener, cocoa powder, and salt to a microwave safe bowl. Melt ingredients using the microwave. Mix until most of the sweetener has melted and the mixture is well incorporated.
Remove from heat and allow the mixture to cool slightly.
Add one egg at a time, mixing well until completely incorporated. The texture should be very thick, with all the sweetener dissolved into the mixture.
Add the almond flour, mix vigorously (I use an electric mixer) until fully blended (about a minute).
Spoon into pan and push down evenly. You might need to put some oil on your fingers and press the dough into the pan.
Bake for 20 minutes or until the center is just set and a toothpick inserted in the center comes out moist but clean.
Allow brownies to cool completely before cutting.
Lift brownies using the edges of the parchment paper and cut into the desired size (we do 16!).
Notes
If your batter is too thick you can add an extra egg. Note, this may make the brownies cakeier rather than fudgy.
To get extra clean edges, place in the freezer for 10 minutes prior to cutting.