Mix the wet ingredients: In a bowl, whisk together the whole eggs, egg whites, avocado oil, Greek yogurt, and vanilla until fully combined.
Combine the dry ingredients: In a separate bowl, mix the almond flour, cocoa powder, sweetener, baking powder, and pinches of instant coffee. That hint of coffee makes the chocolate flavor pop — it’s like adding an espresso touch.
Bring it all together: Gradually fold the dry ingredients into the wet mixture until everything is well incorporated.
Add the extras: Stir in the chopped walnuts and sugar-free dark chocolate chips.
Fill the cupcake liners: Spoon the batter into cupcake molds and top each one with a walnut and a few extra chocolate chips.
Bake: 20 minutes at 375°F, or until a toothpick inserted in the center comes out clean.