Baked Doughnuts

Name: Baked Doughnuts
Prep time: 15 min
Cook time: 1 h
Total time: 1 h
Yield: 12 pieces
Ingredients: 180 g plain flour; 100 g granulated sugar; 1 tsp baking powder; ½ tsp bicarbonate of soda; ¼ tsp fine sea salt; 1 large egg; 1 tsp vanilla extract; 170 g plain yoghurt; 80 g milk; 35 g olive oil; 50 g caster sugar; 1 tsp ground cinnamon; 40 g unsalted butter