01 -
Preheat oven to 350°F (177°C) and line two 12-cup muffin pans with baking liners or lightly grease with nonstick spray.
02 -
In a large mixing bowl, whisk together butter pecan cake mix, all-purpose flour, and baking powder until well combined.
03 -
Add mashed bananas, eggs, and 1 cup of chopped walnuts to the dry mixture. Stir gently until just combined, taking care not to overmix.
04 -
Spoon batter evenly into prepared muffin cups, filling each about two-thirds full.
05 -
Sprinkle the remaining 0.5 cup chopped walnuts over the tops of the muffins.
06 -
Bake on the middle oven rack for 17–20 minutes, or until the muffin tops are golden and a toothpick inserted in the center comes out clean.
07 -
Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to finish cooling or serve warm.