The best diet cake with oats, apple and blueberries!

Ingredients:

2 eggs
pinch of salt
40 g(1/4 cup)sweetener(erythritol, stevia, etc)
120 g yogurt (1/2 cup)
50 ml vegetable oil(3 3/4 tbsp)
1 teaspoon vanilla extract
1 medium/small apple
100 g rolled oats(3.52 oz)
7 g baking powder(1/2 tbsp)
grease with butter/ oil
60 g blueberries(2.11 oz)
bake 35-40 minutes at 180°C/ 360°F