Winter Squash Spoonbread Yield: 8 servings   Spoonbread is somewhere between a soufflé and cornbread, based on a thick sauce known as a rick. Here, I put pureed winter squash — acorn, butternut, or even pumpkin — into the rick with a little maple syrup. This puffs up nicely, but it doesn't stay that way long once it comes out of the oven. It is very good cold, for breakfast, with a little cream and maple syrup drizzled over it. But it's also a fine accompaniment to poultry dishes.   1-1/2 cups peeled and    diced winter squash, (1/2-inch pieces) 1/3 cup pure maple syrup 2 cups milk 1 cup cornmeal, preferably stone-ground 3/4 teaspoon salt 1/8 teaspoon nutmeg 4 tablespoons butter,    cut into 1/2-inch pieces 5 eggs, separated   1. Preheat oven to 375 degrees F. Grease a large, shallow casserole and set aside. 2. Put the squash into a large saucepan with plenty of water. Bring to a boil, cover, then simmer for about 20 minutes, until the squash is very soft. Drain in a colander for several minutes, then puree the squash with the maple syrup in a food processor or blender. Set aside. 3. Pour the milk in a large, heavy-bottomed pot. Gradually whisk in the corn-meal over low heat. Turn the heat to medium-high and cook the cornmeal, stirring, until it starts to thicken, about 3 to 5 minutes. Reduce the heat slightly and continue to stir and cook for several more minutes, until it is quite thick. 4. Stir in the salt, nutmeg, butter, and squash mixture; whisk until smooth. Remove from the heat and whisk in the egg yolks. Pour into a large bowl. 5. Beat the egg whites until stiff, then fold them into the cooked mixture. Pour into the prepared pan and bake for about 35 minutes, until golden and puffed; large cracks will appear on the surface. Serve hot or very warm.   Measuring Tip: Syrup often sticks to the sides of measuring cups and spoons. To make it easier to measure and pour (and to waste less), grease the cup or spoon lightly or coat with vegetable cooking spray before measuring.