2 med. butternut squash (1 1/2 lbs. each)
3/4 tsp. salt
3/4 tsp. pepper
1 med. leek
1 tsp. olive oil
1/2 c. dry white wine
1/2 c. chicken broth
1 c. skim milk
1/2 tsp. sugar
2 slices peasant bread (cut into 4 equal pieces)
4 oz. Gruyere cheese, grated
1 tbsp. plus 1 tsp. grated Parmesan cheese
8 basil leaves, shredded

Preheat oven to 400 degrees. Slice the squash in half lengthwise and remove the seeds. Place the squash, cut side up, in a baking pan. Season with 1/2 teaspoon each of the salt and pepper and cover tightly with aluminum foil. Bake until the squash are tender, but not mushy, about 1 hour. Set aside to cool slightly.

Meanwhile, in a medium saucepan, combine the leek, olive oil and 2 teaspoons of water. Cover and cook over moderately low heat until the leek is soft and translucent, about 5 minutes. Stir in the wine. Increase the heat to high and boil until the liquid is reduced to approximately 3 tablespoons. Stir in the stock, milk, sugar and remaining 1/4 teaspoon each salt and pepper. Remove from heat.

Using a big spoon, scoop the flesh from the squash in large pieces. Place in a medium bowl. To assemble the gratin, preheat the oven to 400 degrees. Bring the leek mixture to a boil. Spoon half of the squash into a 6 to 8 cup oven-proof casserole. Ladle half of the leek mixture over the top and cover with half of the toast and half of the Gruyere cheese. Repeat the layers with the remaining squash, leek mixture, toast and Gruyere. Sprinkle the Parmesan cheese over the top. Bake for 30 minutes or until the top is browned. Garnish with the basil and serve.