2 cups all-purpose flour
2 Tbsp sugar
2 tsp baking powder
1 tsp baking soda
3/4 tsp salt
2 cups well-shaken buttermilk
3/4 stick (6 Tbsp) unsalted butter, melted and cooled to room temperature
2 large eggs
Vegetable oil for waffle iron
2 tablespoons unsalted butter
3-4 firm-ripe large bananas, cut diagonally into 1/3-inch-thick slices
1-1/4 cups pure maple syrup
Put oven rack in middle position and put a large metal cooling rack directly on it. Preheat oven to 250°F and preheat waffle iron.
Whisk together flour, sugar, baking powder, baking soda, and salt in a large bowl.
Whisk together buttermilk, melted butter, and eggs in another bowl, then whisk into flour mixture until just combined.
Brush hot waffle iron lightly with vegetable oil and pour a slightly rounded 1/2 cup of batter into each waffle mold (see cooks’ note, below). Cook waffles according to manufacturer’s instructions until golden and cooked through, about 3 minutes. Transfer as cooked to rack in oven to keep warm, keeping waffles in 1 layer to stay crisp. Make more waffles in same manner.
While last batch is cooking, heat butter in a 12-inch heavy skillet over moderately high heat until foam subsides, then add banana slices in 1 layer and cook until golden, about 1 minute per side. Remove from heat and add syrup to skillet.
Spoon bananas over waffles, then drizzle with warm syrup before serving.
8 Belgian or about 14 regular waffles