- 1 Put potatoes in a large stockpot. Cover with broth and bring to a boil; cook 4 minutes. Remove from heat. Remove potatoes using slotted spoon. Strain cooking liquid; reserve 1-1/2 cups cooking liquid. Discard solids and remaining cooking liquid.
- 2 Melt butter over medium heat in saucepan. Sprinkle flour over butter; cook 1 minute, stirring with a whisk. Add Gourmet Garden Garlic Stir-In Paste; cook 1 minute, stirring frequently. Slowly add milk, reserved cooking liquid and Gourmet Garden Lightly Dried Parsley to flour mixture. Bring mixture to a boil; cook 4 minutes or until slightly thickened, stirring frequently. Remove from heat. Stir in Gruyere cheese and pepper.
- 3 Spread ½ cup cheese sauce on bottom of a 2-qt baking dish sprayed with cooking spray. Arrange a layer of sweet potatoes then a layer of baking potatoes. Top with 1 cup cheese sauce. Top with remaining sweet potatoes and potatoes alternating them in a shingle like manner. Pour remaining sauce over potatoes to cover completely. Sprinkle with Parmesan cheese.
- 4 Bake at 350 degrees for 1 hour or until potatoes are tender when pierced with a knife. Remove gratin from oven.