1Heat the oven to 375°F, position the racks low in the oven, and line 12 muffin cups with paper liners.
2Combine the flour, baking powder, salt, 3/4 cup of the walnuts, and the espresso powder in a bowl and whisk to combine.
3In a separate large bowl or a stand mixer, cream the butter until light and fluffy. Beat in the sugar and then the eggs, one at a time. Stir in the vanilla, yogurt, and mashed bananas, then briefly and gently mix in the dry ingredients; overmixing will result in tough muffins.
4Spoon into the prepared muffin tin (an ice-cream scoop works well), top with the remaining 1/2 cup walnuts, and bake until golden, about 25 mintues. Fill the cups two-thirds full for regular muffins or to the brim for a big-topped version. Cool in the tin for 5 minutes, then turn out onto a wire rack to cool completely.
Reprinted with permission from Super Natural Cooking: Five Ways to Incorporate Whole and Natural Ingredients into Your Cooking by Heidi Swanson. Copyright 2007. Published by Celestial Arts.
This recipe, while from a trusted source, may not have been tested by the CHOW food team.