Make the dough: In the bowl of a stand mixer (or a large mixing bowl), whisk together the sourdough starter, water, melted butter, honey, eggs, and vanilla extract until smooth.Add the flour and salt, then mix until a shaggy dough forms.If using a stand mixer: Attach the dough hook and knead on low speed for 5–8 minutes, or until the dough becomes smooth, elastic, and slightly tackyIf kneading by hand: Turn the dough onto a lightly floured surface and knead for 8–10 minutes, until the dough is smooth, soft, and stretchy. Bulk ferment the dough: Transfer the dough to a lightly greased bowl, cover with a damp towel or plastic wrap, and let it bulk ferment at room temperature for 8–12 hours, or until doubled in size and puffy.
Add leavening. After fermentation, sprinkle baking soda and baking powder evenly over the dough. Knead or mix for about 5 minutes to fully incorporate — this step helps the rolls rise light and fluffy in the oven.
Make the cinnamon filling: In a small bowl, combine softened butter, brown sugar, and cinnamon. Mix until smooth and spreadable.
Roll and fill the dough: Lightly flour your work surface and roll the dough into a ¼-inch thick rectangle (about 12×18 inches). Spread the cinnamon-sugar mixture evenly over the surface, leaving a small border along one long edge. Don't worry if your cinnamon butter doesn't spread well. Instead, crumble it evenly across the dough's surface, and it will melt together while baking!
Shape the rolls: Roll the dough up tightly into a log. Pinch the seam closed to seal, then slice into 12 even rolls using a sharp knife or unflavored dental floss.
Bake: Grease a cast-iron skillet or baking dish, and arrange the rolls evenly inside, leaving a little space between each. Bake in a preheated oven at 375°F (190°C) for 20–25 minutes, or until golden brown and baked through.
Mix the glaze: In a small saucepan over medium heat, whisk together the cream cheese, milk, maple syrup, vanilla extract, and salt until smooth and pourable. If the glaze is too thick, add a splash more milk (1–2 teaspoons at a time) until it easily drizzles off a spoon.
Glaze the rolls: Pour the warm glaze over your cinnamon rolls right after baking for a glossy, sweet finish that melts into every swirl.