18 tbsp. unsalted butter, softened, plus more for greasing
3¼ cups flour, plus more for dusting
2 tsp. kosher salt
1 cup milk
1¼ cup granulated sugar
2 (¼-oz.) packages active dry yeast
2 tsp. ground cinnamon
½ cup packed light brown sugar
1. Grease a 10″ bundt pan with butter and dust with flour; set aside. Whisk flour and salt in a bowl; set aside. Heat 2 tbsp. butter with milk and ⅓ cup water in a 1-qt. saucepan over medium-high heat until an instant-read thermometer reads 115°. Transfer to a mixer fitted with a hook attachment. Stir in ¼ cup granulated sugar and yeast; let sit until foamy, about 10 minutes. With the motor running, slowly add dry ingredients; beat until dough is smooth. Transfer to a lightly greased bowl and cover loosely with plastic wrap; set in a warm place until doubled in size, about 1 hour.
2. Combine remaining granulated sugar with cinnamon in a large bowl. Melt remaining butter in a 2-qt. saucepan; whisk in brown sugar and set aside.
3. Heat oven to 350°. On a lightly floured surface, pat dough out into an 8″ square about 1″ thick. Cut dough into 1-inch pieces. Toss dough with cinnamon sugar mixture, and then fit snugly into prepared bundt pan. Pour butter mixture evenly over dough; bake until golden and a toothpick inserted in the middle of the bread comes out clean, about 35 minutes. Let cool slightly before serving.