Microwave Cake

Ingredients

• 0.5 egg-sized piece butter
• 1 egg
• 15 g flour
• 2.5 g baking powder
• 10 g sugar
• 1 g salt
• optional chocolate
• optional banana
• optional coffee powder
• optional oats
• optional milk
• optional nuts
• optional biscuit crumbs

Method

Melt 50 g butter in a microwave-safe mug or ramekin at full power for 15 seconds. The butter needn't be completely liquid — residual heat will finish the job. Crack one egg directly into the hot butter and whisk hard for 10 seconds. The heat begins to denature the egg proteins immediately, which will trap air when you fold in the dry ingredients. This aeration is your only leavening agent aside from the baking powder, so the vigour of your whisking matters.

Add 10 g caster sugar and 1 g salt. Whisk again until the mixture lightens slightly and turns paler — roughly 20 seconds of continuous whisking. The egg and sugar are emulsifying together; you'll see the texture shift from slick to mousse-like. Add any wet flavourings now — mashed banana, melted chocolate paste, strong black coffee, or a splash of milk — and fold in gently. The mixture should resemble thick yoghurt, with no visible streaks of butter.

Combine 15 g plain flour and 2.5 g baking-powder in a separate bowl. This separation prevents the baking powder from reacting with moisture too early. Sift the dry mixture into the batter and fold with a spatula until no flour is visible and the batter is smooth. Overmixing develops gluten, which will toughen a quick-bread this small, so stop the moment the mixture is homogeneous. Scatter any dry additions — chopped nuts, oat flakes, biscuit crumbs — across the top of the batter rather than folding them in; they'll distribute as the cake rises.

Microwave at full power for 60 to 75 seconds. The cake will dome upward and the surface will lose its wet sheen as microwave-cooking heat penetrates from all sides. Poke the dome gently with a skewer; the crumb should be just set but still slightly tender at the centre. Underbaking by 5 to 10 seconds is preferable — the carryover heat will finish cooking as it cools, leaving the centre tender rather than dense. Let it sit for 30 seconds before eating. The cake firms up slightly and becomes easier to eat with a fork or spoon.