Accompaniment: chipotle lime sour cream dip
Preheat oven to 400°F.
In a shallow baking pan arrange squash, onion, and garlic in one layer and drizzle with oil, tossing to coat. Roast mixture in middle of oven 15 minutes, or until garlic is tender and transfer garlic to a work surface. Roast squash and onion until tender, about 15 minutes more. Discard peels from squash, onion, and garlic.
In a food processor purée squash, onion and garlic with salt and pepper to taste until smooth. Squash purée may be made 2 days ahead and chilled, covered.
Spread about one fourth squash purée on each of 4 tortillas and sprinkle each with about one fourth bell pepper and about one fourth cheese. Top each quesadilla with a plain tortilla, pressing gently together. Spread each side of quesadillas with 1/2 tablespoon butter.
Heat a griddle or 7-inch non-stick skillet over moderately high heat until hot and cook quesadillas, 1 at a time, until golden, about 3 minutes on each side, transferring to a cutting board.
Cut each quesadilla into 6 to 8 wedges and serve warm with chipotle dip.
From the Dinner Co-op