Add the eggs, vanilla, milk, and 1/2 c. melted butter, and mix well. Pour into a greased loaf pan.
Melt the second 1/2 c. butter, and stir in the cinnamon, flour, and brown sugar. Pour on top of the batter and swirl through with a butter knife, making sure to get all the way to the bottom.
Bake for 50-60 minutes, or until done through. Do not over bake--check for doneness with a toothpick.
Cinnamon Glaze
While the cake is baking, place the powdered sugar and softened butter in a bowl Add the milk a little bit at a time until you get the right consistency. Add the vanilla and salt, mix well. Mix in the cinnamon and stir until combined.
When the bread is finished baking, cool for 15 minutes before drizzling the glaze over the top.