Heat oven to 350°F.
Bring milk in saucepan to boiling. Stir together cornstarch, sugar, salt and egg in a small bowl. Stir a small amount of hot milk into cornstarch mixture; stir cornstarch mixture into milk in saucepan. Over medium-low heat, cook milk mixture, stirring, until thickened, about 6 minutes. Remove saucepan from heat. Stir in vanilla. Cover and set saucepan aside.
Add chopped dried cranberries to boiling water in saucepan; let stand to plump.
Melt butter in 10-inch skillet over medium heat. Add apples, 1/2 teaspoon cinnamon and the nutmeg; cook, stirring occasionally, until softened, 7 to 10 minutes. Add brown sugar; cook, stirring to coat apples and until thickened slightly, about 2 minutes. Remove skillet from heat.
Drain cranberries; stir half into apple mixture. Mix water and granulated sugar in small bowl. Brush tortillas with sugar-water. Fill each tortilla with 1/4 cup apple mixture. Reserve 1/3 cup custard for garnish. Top apple mixture in each tortilla with 2 tablespoons custard. Roll up tortillas; place, seam side down, in 12 x 7-inch glass baking dish. Sprinkle enchiladas with remaining cinnamon. Cover tightly with foil.
Bake in 350°F oven for 10 to 12 minutes or until enchiladas are lightly golden brown. Garnish with reserved custard and remaining cranberries. Serve warm.