These little zero carb ‘muffins’ are something of a mini-frittata. They are very rich, so one batch could last you a couple of mornings (they store well in the fridge). Pop them in the microwave for a quick keto-friendly breakfast. Do change up the filling – mushroom, peppers and different cheese all work well. If you can’t be bothered with cleaning the muffin tin (eggs are notorious for sticking), use cupcake cases. One serving = 2 muffins.