Better than Cinnabon Cinnamon Rolls with Buttercream Glaze

10 oz water

1 tsp salt

4 Tbsp. salted butter

4 cups all purpose flour

½ cup packed brown sugar

1 Tbsp. yeast

½ cup salted butter (melted)

1 cup packed brown sugar

1 Tbsp. ground cinnamon

½ cup salted butter (melted (or ½ cup unsalted plus ¼ tsp. salt))

2 cups powdered sugar

2 Tbsp. milk

1 tsp. vanilla extract