Chocolate Mug Cake
five minutes, one mug, real chocolate cake

A mug, a fork, and five minutes from wanting dessert to eating it. Flour, cocoa, sugar, oil, an egg, and milk — everything already in the kitchen — mixed directly in the mug and microwaved into a dense, fudgy chocolate cake. It is not a full-size cake, but it is real chocolate cake, and it is ready before you finish thinking about whether to make it.

The mug cake has a reputation for being rubbery and disappointing, and that reputation is earned by over-microwaving. Cocoa powder and egg protein set very quickly in a microwave, and the margin between just-cooked and overdone is about 20 seconds. The goal is to stop the microwave when the cake looks almost but not quite done in the center — it finishes cooking from its own internal heat during the resting minute. If you wait until the top looks completely dry and set, you have gone 15 seconds too far.

The fat ratio matters too. Three tablespoons of oil or melted butter relative to the other ingredients keeps the crumb tender. Drop below that and the cake dries out. A tablespoon of extra chocolate chips pushed into the batter before microwaving creates a small molten chocolate pool in the center, which is very much worth doing if you have them.

What you need

• 4 tablespoons all-purpose flour (plain flour)
• 4 tablespoons granulated sugar
• 2 tablespoons unsweetened cocoa powder — Dutch-process or natural both work; Dutch-process gives a darker, less bitter cake
• 1 large egg
• 3 tablespoons milk — any type; plant milks work equally well
• 3 tablespoons neutral oil, or melted butter — butter gives a richer flavor
• ¼ teaspoon vanilla extract
• Pinch of salt
• 2 tablespoons chocolate chips — optional but strongly recommended
• A mug with at least 350ml capacity — the cake rises significantly and will overflow a small mug

How to make it

Step 1: Mix the dry ingredients. Add the flour, sugar, cocoa powder, and salt directly into the mug. Use a fork to mix them together until there are no visible cocoa clumps. This step is worth doing carefully — a pocket of unmixed cocoa in the batter creates a bitter, powdery spot in the finished cake. Thirty seconds of thorough mixing prevents this.

Step 2: Add the wet ingredients. Crack the egg directly into the mug. Add the milk, oil or butter, and vanilla. Stir with the fork, mixing from the bottom up, until the batter is smooth and no dry flour streaks remain. Scrape the sides and bottom of the mug with the fork to catch any dry ingredients clinging to the edges. The batter should be glossy and quite thick — similar to a brownie batter. If it looks too dry, add an extra teaspoon of milk.

Step 3: Add chocolate chips. If using chocolate chips, stir them into the batter now. Reserve a few to press into the top if you want a visual effect. Check that the batter fills no more than halfway up the mug — the cake will roughly double in height as it cooks, and it will overflow a full mug.

Step 4: Microwave. Place the mug in the center of the microwave. Cook on full power for 60 seconds. Open the microwave and check: the cake should be risen, pulling away from the sides of the mug slightly, with a surface that looks mostly set but still slightly glossy in the very center. This is correct. If the center looks completely raw and wet, microwave in additional 10-second bursts. Every microwave is different — the range is typically 60 to 90 seconds total. Do not microwave past the point where the surface is set all the way through, or the cake will be rubbery.

Step 5: Rest and serve. Let the mug stand on the counter for one minute before eating. The cake continues to cook gently from residual heat and will firm up from very soft to a proper cake texture during this rest. Eat directly from the mug, or run a butter knife around the edges and invert onto a small plate. Top with a scoop of vanilla ice cream, whipped cream, or a spoonful of peanut butter if available.

Getting it right: the timing issue

Microwave wattages vary significantly — a 700W microwave needs closer to 90 seconds; a 1200W microwave may be done in 60. The first time you make this, err on the short side and check early. You can always add 10 more seconds, but you cannot uncook an overdone mug cake. The ideal result is a cake that is fully cooked at the edges and bottom, with a center that is just barely set — almost like a very dense chocolate pudding. This is a feature, not undercooking.

Chef notes

Adding a tablespoon of peanut butter swirled into the batter before microwaving creates a peanut butter-chocolate version. A pinch of espresso powder added with the dry ingredients intensifies the chocolate flavor without tasting like coffee. A small square of dark chocolate pressed into the center of the batter before cooking creates a lava-cake effect where the center stays molten.

Variations

• Gluten-free version: Substitute the all-purpose flour with the same volume of almond flour or gluten-free flour blend. The texture will be denser and more brownie-like.
• Nutella mug cake: Replace the cocoa powder with 2 tablespoons of Nutella and reduce the sugar to 2 tablespoons. Richer and sweeter.
• Vanilla mug cake: Replace the cocoa with an extra tablespoon of flour and increase the vanilla to ½ teaspoon. Add a handful of sprinkles for a funfetti version.

See also: Banana oat pancakes · French toast from stale bread · Coconut milk overnight oats · All recipes · Pricing