Preheat the oven to 350F. Line a baking sheet with a piece of parchment or a nonstick pad. Set aside.
In the bowl of a stand mixer using the whisk attachments, beat together the peanut/nut/seed butter and eggs. (You can also use a large, sturdy mixing bowl and a hand mixer, if you prefer.).
Add the coconut oil and vanilla, and beat until combined.
Add the stevia, baking soda and sea salt, and beat until well incorporated.
Scoop 1 1/2 Tablespoon portion of dough and roll into a ball between the palms of your hands. Flatten slightly and place on cookie sheet.
Repeat with the remaining dough, spacing cookies evenly (at least 1" apart) on the cookie sheet.
Bake for 13-17 minutes until cookies are puffy and very slightly cracked on top.
Remove from oven and either gently press one chocolate kiss into the center of each cookie or press the lightly greased back of a 1 teaspoon measuring spoon into the center of each cookie to form a little well.
Allow cookies to cool and firm up at room temperature.
If you're filling your cookies with ganache, wait until they have firmed up and cooled slightly before combining the chocolate and coconut oil in a microwave-safe bowl.
Microwave on high for 30-60 seconds until melted and stir able. Stir until smooth, then stir in the cocoa powder.
Use a spoon or pastry bag to fill the holes you created in the centers of the cookies with ganache.
Allow the ganache to completely set at room temperature before serving or storing cookies.
Do not use the no-stir nut/seed/peanut butter. It will negatively affect the consistency of the cookies!
Store cookies in an airtight container at room temperature for up to 5 days, or in the freezer for up to 3 months.