12 lb butternut squash, halved lengthwise and seeded
1 1/2 tablespoons chopped fresh jalapeño chile, including seeds
1 teaspoon ground cumin
7 cups chicken broth or water
5 cups water plus additional for thinning
1 tablespoon fresh lemon juice, or to taste
Accompaniment: pumpkin seed pesto
Directions
Preheat oven to 400°F.
Trim and discard crusts from bread. Spread 1 side of each slice evenly with butter and season with salt and pepper. Halve slices diagonally to form triangles and arrange, buttered sides up, on a baking sheet. Toast bread, turning once, in middle of oven until golden brown, about 4 minutes. Transfer toasts to a rack to cool.
Put squash, cut sides down, in 2 greased shallow baking pans and roast in upper and lower thirds of oven, switching position of pans halfway through roasting, until very tender, about 1 1/4 hours. Cool and scoop out flesh.
Purée squash in batches in a blender with jalapeño, cumin, and broth until very smooth (add additional water as needed to facilitate puréeing).Transfer to a 6- to 8-quart heavy pot and stir in 5 cups water. Simmer, stirring, 10 minutes, then stir in lemon juice, enough water to thin to desired consistency, and salt and pepper to taste.
Serve soup in bowls topped with slices of toast spread with pesto.
