Cinnamon Bun Bundt Cake

INGREDIENTS

• 6 tablespoons (3/4 stick) unsalted butter, at room temperature
• 1/8 teaspoon salt
• Vegetable oil for the bowl
• 3/4 cup buttermilk
• 1/4 cup plus 1 teaspoon granulated sugar
• 1 tablespoon ground cinnamon
• 1 envelope (1/4 ounce, 2 1/2 teaspoons) active dry yeast
• Flour for the work surface
• 4 large egg yolks
• 1/4 cup warm water (105° to 110°F)
• 4 tablespoons (1/2 stick) unsalted butter, melted, plus more for the pan
• 3 1/2 to 4 cups all-purpose flour (spooned into cup and leveled off)
• 2/3 cup plus 3 tablespoons packed light brown sugar
• 1 teaspoon salt