Microwave on high (1000 Watts). Adjust time if needed. Gluten-free flour works well too. Do not overcook the mug cake; it continues cooking as it cools. Optionally bake in oven at 350°F/180°C for 25-30 minutes in an oven-safe ramekin. Store leftovers covered in fridge for 1-2 days, warm before eating.