For dough: Heat milk, water and butter in small saucepan until the butter melts. Remove from heat and set aside until the mixture cools to between 120 to 130°F. Beat the milk mixture, sugar, egg and yolks, salt, yeast and 2 cups of flour in a large bowl with electric mixer at low speed for 2 minutes.
Add enough remaining flour to make a soft dough. Turn dough onto lightly floured surface; knead until smooth and elastic about 6 to 8 minutes. Place in greased bowl; turn greased side up. Cover and let rise in a warm, draft-free place about 1-1/2 hours.
Punch dough down. Press into greased 12 or 14-inch pizza pan (with sides). Cover loosely with plastic wrap and let rise until doubled, 1-1/2 to 2 hours.
Preheat oven to 350°F.
For topping: toss apple slices with lemon juice and peel in a large bowl. Combine the sugar and spices in a small bowl. Lightly brush dough with 1 to 2 tablespoons of honey, leaving 1/2-inch border around the edge. Sprinkle graham cracker crumbs on top of honey. Arrange apple slices on coffeecake. Top with sugar mixture.
Bake for 25 to 30 minutes. Cool for 30 minutes.
Mix all icing ingredients together until smooth, adding enough milk for desired consistency. Drizzle over coffeecake.