Step 1

Line a 10 1/2– by 5 1/2–inch loaf pan with a 9- by 13-inch sheet of parchment paper, or two 9- by 5-inch loaf pans with 7- by 13-inch sheets of parchment paper. Adjust oven rack to lower-middle position and preheat to 350°F. Peel bananas (for roughly 12 ounces or 340g fruit) and mash with Greek yogurt, eggs, and vanilla in a medium bowl. If bananas are underripe, cover bowl with plastic and let mixture stand 30 minutes.

Step 2

Combine flour, sugar, oat flour, baking powder, baking soda, salt, cinnamon, cloves, nutmeg, and coconut oil in the bowl of a stand mixer fitted with a paddle attachment. Mix on low until coconut oil disappears into a mealy powder. Add banana mash and continue mixing only until the floury bits disappear. Fold in nuts with a flexible spatula, scrape into prepared pan(s), and spread into an even layer. Bake until well risen and golden brown, or to an internal temperature of around 206°F (about 70 minutes for a large loaf or 45 for small). Wrapped tightly in foil, banana bread will keep up to 3 days at room temperature or 1 week in the fridge.

Step 3

For Banana Nut Muffins: Divide batter evenly among 12 lightly greased nonstick muffin cups, adding approximately 1/2 cup (4 ounces; 120g) to each cup. Bake until domed and just beginning to brown around the edges, about 25 minutes.