Whisk together 1 egg, 1 teaspoon of light olive oil, 1/2 teaspoon of vanilla extract, and 1/2 teaspoon of apple cider vinegar in a microwave-safe mug until fully combined. Add 1/3 cup of almond flour, 2 tablespoons of cane sugar, 1 teaspoon of cocoa powder, 1/4 teaspoon of baking powder, 1/2 teaspoon of beetroot powder, and 3 pinches of salt to the mug. Stir the mixture until a smooth batter forms.