1. Preheat oven to 375°F. Whisk together 6 eggs, milk, salt and pepper. Melt butter in large nonstick skillet over medium-low heat; pour in egg mixture. Cook, stirring frequently, for 5 to 8 minutes or until eggs are set and soft curds have formed. Let cool completely.
2. On lightly floured surface, roll out pastry; cut into 4- x 3-inch rectangles, rerolling scraps to make 16 rectangles.
3. Whisk remaining egg with 1 tsp. water; brush some over edges of 8 pastry rectangles, reserving remaining egg wash. Top pastry rectangles with ham, scrambled eggs and cheese. Cap with remaining rectangles. Press edges firmly with fork to seal.
4. Transfer to parchment-paper–lined baking sheets, about 2 inches apart. Freeze for 10 minutes.
5. Lightly brush each tart with remaining egg wash. Pierce top of each tart with knife to make steam vents. Bake for 25 to 30 minutes or until golden and flaky.
6. Make-ahead: Let toaster tarts cool completely; refrigerate for up to 3 days or freeze for up to 2 weeks. Reheat in toaster oven.
Use your favorite Cheddar cheese – mild, medium or aged.