Sticky Ginger Buns

Name: Sticky Ginger Buns
Ingredients: 8 tablespoons (1 stick) unsalted butter; 1/2 cup whole milk; 2 tablespoons honey; 1 (1/4-ounce) packet active dry yeast (2 1/4 teaspoons); 2 large eggs; 1 1/2 cups all-purpose flour, plus more for rolling; 1 cup whole wheat flour; 2 teaspoons ground ginger; 1 teaspoon kosher salt; 6 tablespoons (3/4 stick) unsalted butter, divided; 1/2 cup honey; 1 teaspoon ground ginger; 1/2 teaspoon cayenne pepper; 1/3 cup finely chopped crystallized ginger; 1 cup granulated sugar