Brown Sugar Cinnamon Mug Cake

Use a microwave-safe mug with at least a 12-ounce capacity.

In the mug, whisk together the flour, 2 tbsp brown sugar, baking powder, 1/8 tsp cinnamon, and salt.

Add the milk, 1 tbsp melted butter, and vanilla. Stir only until no dry flour remains. Do not aggressively overmix.

In a small bowl or spoon, combine 1 tbsp brown sugar, 1/4 tsp cinnamon, and 1 tsp melted butter.

Spoon the cinnamon mixture over the mug-cake batter. Use the tip of a knife or toothpick to gently swirl it through the upper portion of the batter. Do not completely mix it in.

Wipe any batter from the upper inside walls of the mug.

Microwave on HIGH for 60 seconds. Check the cake — the edges should look set while the center remains soft and moist.

If necessary, microwave in additional 10-second intervals until just cooked. Most microwaves should require approximately 60–90 seconds total.

Let the mug cake stand for 1–2 minutes before eating. The mug will be very hot.

Serve warm, optionally with a small amount of vanilla ice cream or whipped cream.