
Preheat oven to 400 degrees with rack in center.
In a large bowl, whisk together eggs, cream, 3/4 teaspoon salt, and 1/4 teaspoon pepper. Stir in turkey, spinach, half the bacon pieces, and 3/4 cup cheese. Pour into a buttered 9-by-13-inch baking dish. Sprinkle with remaining half of bacon pieces and 3/4 cup cheese.
Bake until set, 18 minutes. Switch oven to broil and cook until browned in places, about 3 minutes more. Let cool slightly.
Meanwhile, stir together equal parts mustard and mayonnaise. Slice frittata into 8 rectangles. Serve between or atop slices of toast with Dijonnaise.