Snack

Chocolate Protein Mug Cake

Name: Chocolate Protein Mug Cake
Prep time: 5 min
Total time: 5 min
Yield: 1 serving
Ingredients: 1 scoop, about 30 g Whey protein isolate; 2 tsp, about 6 g Cocoa powder; 20 g Rolled oats; 1 white, about 33 g Egg white; 40 ml Skimmed milk; Half a teaspoon Baking powder; To taste Granulated sweetener; A pinch Salt

A scoop of whey, cocoa, oats and an egg white, cooked in a mug in ninety seconds. 33 g of protein for 238 kcal.

Calories: 238kcal
Protein: 33g
Fat: 3g
Carbs: 17g

Per serving, makes 1. 5 minutes of work. Published 8 September 2026.

Allergens

Gluten
Milk
Eggs

Most whey powders contain soya lecithin, which counts as soya. Check the tub.
Oats count as a gluten cereal under UK labelling and ordinary oats are milled alongside wheat. Certified gluten-free oats are a separate ingredient here.

Flags follow UK labelling rules and come from the ingredients as listed, not from any particular brand. Check the packet before cooking for somebody with an allergy.

Ingredients

Whey protein isolate1 scoop, about 30 g
Values for an unflavoured or lightly flavoured isolate. A concentrate or a blend carries more fat and carbohydrate at the same scoop.
Cocoa powder2 tsp, about 6 g
Rolled oats20 g
Blitzed to a flour if you have a grinder; left whole they give a rougher cake that still works. Dry weight.
Egg white1 white, about 33 g
Skimmed milk40 ml
Baking powderHalf a teaspoon
Granulated sweetenerTo taste
SaltA pinch

Method

Mix the whey, cocoa, oats, baking powder, sweetener and salt in a large mug with a fork so there are no lumps of powder.
Add the egg white and milk and beat until smooth. The batter should drop off the fork slowly; add a splash more milk if it is stiff.
Microwave on full power for seventy to ninety seconds. Stop when the top looks set but still glossy. It carries on cooking in the mug, and a minute too long makes it rubbery.

Worth knowing

Whey does not bake the way flour does. It sets like a firm sponge and turns to rubber if overcooked, so the timing is tight and the oats are there to soften it.
Microwaves vary. Try seventy seconds the first time and add ten if the middle is wet.

Other snack recipes that share ingredients with this one, or every snack under 300 calories a serving.

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Macros are calculated from the weights listed above using standard food composition values, and will shift with your own brands and measuring. Weigh what you can. This is a recipe, not dietary advice. The full health disclaimer is below.