Butternut Squash Flan with Parmesan Sage Sauce

Ingredients

• 2.5 pound butternut squash halved lengthwise seeded
• 4 large egg yolk 
• 2 cups half and half 
• 1.1 ounce parmesan finely grated ()
• 8 servings sage fresh
• 4 large sage fresh finely chopped

Equipment

• food processor
• bowl
• frying pan
• sauce pan
• oven
• knife
• whisk
• sieve
• baking pan
• cake form
• wooden spoon
• kitchen thermometer
• wax paper
• skewers

Directions

1. Put oven rack in middle position and preheat oven to 400°F.
2. Roast squash, cut sides down, in a lightly oiled shallow baking pan until neck is tender, about 1 hour.
3. Remove from oven and reduce oven temperature to 325°F. Cool squash to warm.
4. Butter an 8- by 2-inch round cake pan. Line bottom with a round of parchment or wax paper and butter paper.
5. Scoop flesh from squash, discarding skin, and purée in a food processor until smooth, about 45 seconds. Put 2 cups purée in a bowl, then whisk in whole eggs, 1 cup half-and-half, 2 tablespoons cheese, 1 1/4 teaspoons salt, and 1/2 teaspoon black pepper until combined.
6. Pour squash mixture into cake pan and bake in a water bath until just set and a wooden pick or skewer comes out almost clean, 45 minutes to 1 hour.
7. Remove from water bath and cool flan in pan on a rack 15 minutes. Invert a flat plate over flan, then invert flan onto plate and carefully remove parchment.
8. Meanwhile, bring whole sage leaves and remaining cup half-and-half just to a simmer in a 1- to 2-quart heavy saucepan, then remove from heat and let steep, covered, 10 minutes.
9. Remove sage, carefully squeezing leaves to extract liquid, and discard leaves.
10. Whisk yolks into half-and-half and cook over moderately low heat, stirring constantly with a wooden spoon, until sauce is thick enough to coat back of spoon and registers 170 to 175°F on thermometer, about 4 minutes (do not let boil).
11. Immediately pour sauce through a fine-mesh sieve into a bowl, then add remaining 1/2 cup cheese and chopped sage, stirring until cheese is melted. Stir in 1/4 teaspoon salt and 1/2 teaspoon pepper.
12. Cut flan into wedges with a thin knife, wiping knife clean after each slice.
13. Serve flan with sauce.