Preheat oven to 425 degrees. In a medium skillet, heat butter over medium heat. Cook spinach for 5 minutes, or until tender. Cool slightly. Stir in sage and pepper. Sprinkle flour on a baking sheet without sides. Place pie crust on top, and roll to a 14-inch round. Spread spinach mixture over dough, leaving a 2-inch border. Sprinkle half the cheese over the top. Arrange tomatoes in 2 circles over the top; sprinkle with remaining cheese. Fold over edges of dough; pinch to make a border. Lightly beat eggs, brush egg over outside dough. Pour remaining mixture over tomatoes and cheese. Bake for 10 minutes at 425 degrees. Reduce oven temperature to 375 degrees and bake 15 minutes longer or until golden brown and eggs are cooked.