Preheat oven to 350°F. Spray a 9x13-inch baking pan with a nonstick spray.
Mix and bake the cake mix according to the directions on the box and allow it to cool.
15.25 ounces yellow cake mix, 1 cup water, 3 large eggs, ⅓ cup vegetable oil
Using the top of a wooden spoon, poke holes into the cake, so the whole cake is covered in holes.
Combine the pudding mix, milk, and cinnamon in a medium mixing bowl just until it's combined. Pour the pudding all over the cake.
3.4 ounces vanilla pudding mix, 2½ cups milk, 1 tablespoon ground cinnamon
Cover the cake and place it into the refrigerator for 30 minutes. Hide a plastic baby in the cooled cake, if desired.
Whisk together the sugar and half of the milk in a large mixing bowl until it's smooth; if it's too thick, you can add in a little bit of the milk at a time. You want it to be thin enough to pour the glaze but not too thin that it just runs right off the cake.
4 cups powdered sugar, ½ cup milk
Pour the glaze over the cake in an even layer.
Sprinkle the decorating sugars over the top of the glaze.
Decorating sugar