In a stand mixer, combine the bubbly sourdough starter, flour, brown sugar, cinnamon, melted butter, warm milk, and salt. Mix on medium speed until a smooth, elastic dough forms, about 5 minutes.

Transfer the dough to a lightly greased bowl, cover with a damp cloth or plastic wrap, and allow to rise in a warm, draft-free area until it doubles in size, about 1 to 2 hours.

After the first rise, gently punch down the dough, roll it into a large rectangle, brush melted butter, sprinkle brown sugar and cinnamon, and roll tightly before cutting into rolls.

Arrange the sliced rolls in a circular wreath shape on a parchment-lined baking sheet and cover loosely. Let them rise again until puffy, about 30 to 45 minutes.

Preheat your oven to 375°F (190°C) and bake the wreath for about 25 to 30 minutes, or until golden brown.

While the wreath is still warm, whisk together the apple cider and powdered sugar for the glaze, and drizzle generously over the rolls.

Allow to cool slightly before slicing and serving. Best enjoyed warm with coffee or tea.