With a pastry cutter, cut the cold butter, brown sugar, cinnamon and flour together until it is crumbly. The crumbs should be about the size of the pea or a little larger. They will not be uniform in size
Add half of the batter to a prepared pan. Add 3-4 tablespoons of the streusel mixture on top.
Spoon the rest of the batter in top and even it out
With a knife, swirl the batter together just a little bit (optional)
Add the rest of the streusel topping evenly over the top of the batter
Bake uncovered in the preheated oven for 55 minutes or until a toothpick inserted in the center comes out clean (could be longer depending on the oven)
Whisk together the powdered sugar and milk until it is smooth. Only add 2 teaspoons at first to see if it's the right consistency. If it is still dry or lumpy add ½ teaspoon at a time until it is smooth
Let the bread cool for 10 minutes then with a knife, loosen it from the edges. After it is completely cool, carefully remove it from the pan and put it on a serving dish
Drizzle the icing over the top. Serve and enjoy!