Frozen piecrusts let you bake without the fuss, but the thin store-bought shell tends to bake up soggy. The trick? Before filling the crust, seal the dough by sprinkling it with 3 Tbs. of grated Parmesan cheese and 1 tsp. of flour. When baked, the melted cheese mixture will create a flavorful barrier between the moist filling and the crisp crust.