Preheat oven to 350 degrees. Spray a 9x13-inch glass pan with cooking spray. Set aside.
In a stand mixer, add the flour, salt, sugar, baking powder, milk, eggs and vanilla.
Once combined well, slowly stir in melted butter. Pour into prepared pan.
Topping: In a large bowl, cream butter, brown sugar, flour and cinnamon together until well combined and creamy.
Drop evenly over batter by the tablespoon and use a knife to marble/swirl through the cake.
Bake at 350 degrees for 35-40 minutes or when toothpick inserted near center comes out nearly clean.
Glaze: In a medium bowl, combine glaze ingredients and drizzle evenly over warm cake. Serve warm or at room temperature.