1 3/4 cups unbleached all-purpose flour
1 teaspoon baking soda
1/2 teaspoon salt
6 large very ripe bananas, peeled of course
1 stick unsalted butter, melted and cooled slightly
2 large eggs
3/4 cup packed light brown sugar
1 teaspoon vanilla extract
2 teaspoons banana extract
1/2 cup walnuts, toasted and coarsely chopped
2 teaspoons coarse granulated sugar (demerara or muscovado)
Preheat oven to 350F. Prepare your muffin tin with muffin liners.
Whisk flour, baking soda, and salt together in large bowl.
Place 5 bananas in microwave-safe bowl; cover with plastic wrap and cut several steam vents in plastic with paring knife. Microwave on high power until bananas are soft and have released liquid, about 5 minutes. Transfer bananas to fine-mesh strainer placed over medium bowl and allow to drain, stirring occasionally, 15 minutes (you should have 1/2 to 3/4 cup liquid). Note that at this point, the banana mass is not very attractive looking. Transfer liquid to small saucepan and cook over medium-high heat until reduced to 1/4 cup, about 5 minutes. Remove pan from heat, stir reduced liquid into bananas, and mash with potato masher until fairly smooth. Whisk in butter, eggs, brown sugar, vanilla and banana extracts.
Pour banana mixture into flour mixture and stir until just combined with some streaks of flour remaining. Gently fold in walnuts. Scoop batter into muffin tins, to about 3/4 full. Slice remaining bananas diagonally into 1/4-inch-thick slices. Place a banana slice on top of the muffins. Sprinkle coarse sugar evenly each muffin.
Bake until toothpick inserted in center of a muffin comes out clean, 25-30 minutes. Cool muffins in pan on wire rack 15 minutes, then remove from pan and continue to cool on wire rack. Serve warm or at room temperature.
* Why do I call these triple banana when there are only bananas and banana extract in them (meaning, two not three banana ingredients)? By extracting the banana juice from them in the microwave, reducing and then reincorporating, it gives it an intense, or third punch of banana-ness. Or, you can consider the additional slice of banana on the muffin tops as a third incarnation of banana-ness. You decide.
Also, you can make these muffins as a loaf of banana bread as well, by simply using a prepared 8 x 4 inch loaf pan and baking for 55-65 minutes.