Creamy Shrimp and Pasta Seashells

Preheat oven to 400°F (200°C).

Sauce:
In saucepan, melt butter over medium heat; whisk in flour and cook, whisking, for 1 minute. Gradually whisk in milk and bring to boil; reduce heat to medium-low and cook; stirring, for 10 minutes or until thickened. Remove from heat. Stir in cream cheese, 1/2 cup (125 mL) of the Parmesan, lemon rind, salt and pepper until melted; set aside.

Set aside 1 cup (250 mL) of the shrimp; cut remaining shrimp and crab into bite-size pieces. Set aside. In saucepan of boiling salted water, cover and cook broccoli for 3 minutes or until tender-crisp; drain well. In large bowl, stir together broccoli, chopped shrimp, crab and 3-1/2 cups (875 mL) of the sauce for filling; set aside.

In large pot of boiling salted water, cook pasta for 12 to 15 minutes or until tender but firm. Drain and rinse in colander under cold water; drain again, gently shaking colander. Select 24 of the best shells; spoon enough of the filling into each to fill completely without overflowing. Place on damp towel.

Chop remaining shells coarsely; add to remaining filling along with 1-1/4 cups (300 mL) of the remaining sauce. Spoon into 13 x 9-inch (3 L) baking dish. Arrange stuffed shells, filling side up, over top. Arrange reserved whole shrimp over shells. Drizzle with remaining sauce. Sprinkle with remaining Parmesan. (Make-ahead: Can be prepared to this point and refrigerated for up to 1 day.)

Bake, covered with foil, in oven for 40 minutes. Uncover and bake for 20 minutes longer or until bubbling and golden. Serve with lemon wedges.