Ingredients:

2-3 medium Sweet Potatoes
2 medium turnips
3/4 cup butter, divided
1 tablespoon sugar
2 tablespoons chopped fresh dill
salt and white pepper to taste
3/4 cup heavy cream
1 cup fresh breadcrumbs

Preparation:

Preheat oven to 350 F. Peel sweet potatoes and turnips. Grate in food processor to yield 4 cups grated sweet potatoes and 2 cups grated turnips.
In a large sauté pan, melt 1/2 cup butter with sugar. Stir in grated vegetables and sauté 5 minutes. Cover and simmer 5 minutes more. Season with dill, salt and pepper to taste.
Spoon mixture into a greased 8 x 8 inch casserole or individual 4-inch au gratin dishes.
Evenly drizzle heavy cream over mixture.
In a small bowl, combine breadcrumbs with remaining 1/4 cup butter, melted, and spread on top of casserole. Bake 30 minutes.