In a small bowl, stir together the flour, cocoa/cacao powder, sugar and salt. Pour in the melted butter then add the yogurt, milk, peanut butter and vanilla extract and stir just until combined.
Pour the batter into the mug and cook in the microwave on high for 2 minutes.
Let the cake sit for a couple of minutes before serving with a dollop of EasiYo Vanilla Yogurt and a dusting of icing sugar.
