Peanut butter layer cake

Name: Peanut butter layer cake
Cook time: 1 h 15 min
Total time: 1 h 15 min
Cuisine: American
Ingredients: 100g slightly salted butter softened; 200g crunchy peanut butter; 250g light muscovado sugar; 3 large eggs; 250g mashed weight (see tip very ripe, black bananas below); 125g natural yogurt; 1 tsp vanilla extract; 250g self-raising flour; 1 tsp baking powder; 2 tsp cinnamon; 1 tsp ground nutmeg; a small handful honey-roast peanuts chopped for the top; 330g slightly salted butter softened; 75g smooth peanut butter; 650g icing sugar sifted; 2 tsp vanilla bean paste; 3 tbsp milk