Ingredients
1 3/4 cups unbleached all-purpose flour
1 teaspoon baking soda
1/2 teaspoon salt
5 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
12 teaspoons nutella
for the streusel topping
5 tablespoons unsalted butter, cold
1/2 all-purpose flour
1/3 cup light brown sugar, packed
1/4 cup hazelnuts, toasted and chopped
Directions
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.
Scoop batter into muffin tins, to about 1/3 full. Scoop in a tablespoon of nutella and then fill with more batter until muffins are about 3/4 full. Let sit while you make the streusel.
To make streusel topping: Place toasted chopped pistachios in food processor bowl. Pulse machine on/off until you get small, coarse pieces. Add melted butter, flour, and brown sugar to bowl. Using on/off pulse again, process together into even, large crumbs. Sprinkle over muffins before baking.
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.