Frozen or fresh blueberries can be used in this cake. The blueberries make the cake jammy and sweet.

Recipe (sugar free, oil free):
Serves 1,
Spelt flour – 3tbsp
Oats – 2tbsp
Fat free plain yogurt – 3tbsp
Lemon juice – 1/4tsp
Blueberries – 2tbsp
Baking powder – 1/4tsp

Oven temperature 180°C
Air fryer temperature 180°C

Mix all of the ingredients together in a dish. Cover the dish with foil. Bake for 16 minutes in the oven or in the air fryer.

Original recipe:
Jam Doughnut In A Mug by cakeontherun (Instagram)