Thaw shrimp, if frozen. Preheat oven to 350 degrees F. Peel and devein shrimp, removing tails. Rinse shrimp; pat dry with paper towels. Chop shrimp and set aside.
Cook macaroni according to package directions. Drain and keep warm.
In large bowl stir together eggs, butter, half-and-half, 1 cup of the fontina cheese, 1/4 cup of the Parmesan cheese, garlic, pine nuts, chopped basil, and 1/4 teaspoon each salt and pepper. Stir in shrimp and macaroni. Transfer to buttered 2-quart casserole. Top with remaining cheeses.
Bake, uncovered, 40 to 45 minutes or until heated through and shrimp pieces are opaque. Let stand for 10 minutes before serving. Top with fresh basil leaves. Makes 6 servings.