Preheat oven to 400 degrees and line muffin pan with liners
Place almonds in food processor and pulse until very finely chopped
Add bananas and process until combined
Add eggs, vanilla, stevia, cocoa powder, baking soda, vinegar and process until combined, scraping sides with spatula as needed
Pour batter into muffin pan
Bake for 15 minutes or until toothpick inserted in center comes out clean
Whisk all frosting ingredients together
Frost cupcakes once completely cooled