Pecan Waffles with Sauteed Pineapple

Stir together yeast, warm water, and 1 teaspoon sugar in a small bowl and let stand until foamy, about 5 minutes.

(If mixture doesn't foam, discard and start over with new yeast.)

Whisk together eggs, buttermilk, and oil.

Sift together flour, baking powder, baking soda, salt, and remaining 2 tablespoons sugar into a large bowl.

Add egg mixture and whisk until combined but still lumpy.

Add yeast mixture and whisk until combined but still lumpy.

Chill batter, covered, at least 8 hours.

Bring batter to room temperature, then stir in 1 cup finely chopped pecans.

Melt butter in a 12-inch heavy skillet over low heat and scrape seeds from vanilla bean into butter (save pod for another use).

Increase heat to moderately high, then cook pineapple, stirring occasionally, until heated through, 8 to 10 minutes.

Keep warm, covered.

Preheat oven to 250F and preheat waffle iron.

Brush waffle iron lightly with vegetable oil and spoon batter into iron, using about 1 1/2 cups for 4 (4-inch) square Belgian waffles and spreading evenly.

Cook according to manufacturer's instructions, then transfer directly onto oven rack to keep warm.

(Don't stack waffles; they will stay crisp if kept in 1 layer.)

Serve waffles topped with pineapple and sprinkled with remaining 1/2 cup (coarsely chopped) pecans.