Banana Nut Muffins Recipe

Name: Banana Nut Muffins Recipe
Prep time: 10 min
Cook time: 20 min
Total time: 30 min
Cuisine: British
Ingredients: 90 g of creamy butter; 140 g brown sugar; 3 ripe bananas; 1 yogurt; 240 g of flour; 80 g of walnuts, slightly cracked; 2 eggs; 1/2 teaspoon salt; 1 teaspoon cinnamon; 1/2 envelope of baking powder (Royal type) or baking powder; Another 20 g more of walnuts and a couple of tablespoons of brown sugar, to decorate