Preheat oven to 350° Fahrenheit. Adjust oven racks as needed so donuts bake in center of oven. Grease donut pan with cooking spray or butter, making sure to coat sides and edges well. Set pan aside.
Add almond flour, granular Swerve, baking powder, and salt to large mixing bowl. Whisk until dry ingredients are well-blended.
Crack eggs directly into mixing bowl with dry ingredients, then add melted butter, whole milk, and vanilla extract. Whisk until ingredients are fully combined and donut batter forms.
Pour or scoop approximately ¼ cup of donut batter into each cavity of grease donut pan, being careful not to overfill cavities.
Place filled donut pan in preheated oven. Bake 10 minutes, then begin checking doneness of donuts. Continue baking, checking every few minutes, until donuts are deep golden-brown in color.
Once donuts are ready, carefully remove donut pan from oven and set aside. Let donuts cool in pan 10 minutes.
After 10 minutes, run butter knife around inner and outer edges of donuts as needed, then carefully remove donuts from pan and transfer to wire cooling rack. Let donuts cool completely. While donuts cool, prepare vanilla or chocolate glaze (or both).