Heat oven to 375°F. Place pie crust in 9 1/2-inch glass deep-dish pie plate as directed on box for One-Crust Filled Pie. Spoon dollops of dulce de leche into crust, spreading to edges. Place in refrigerator. In medium bowl, beat eggs, pumpkin, brown sugar, flour, vanilla, salt, cinnamon, ginger and nutmeg with whisk until smooth. Beat in milk. Pour filling over dulce de leche in crust.
Bake on lower oven rack 48 to 50 minutes or until pie is just set (center will still jiggle slightly). Cool completely on cooling rack, about 2 hours. Garnish with whipped cream and toffee bits.