Warm the butter & milk in a small saucepan or in the microwave until the butter is just melted and the mixture is warm throughout.

In the bowl of a stand mixer, combine the foamy starter, egg, & vanilla sugar, then beat together with the paddle attachment on low, until smooth. With the stand mixer still on low, stir in the milk mixture until incorporated.

Next, in a separate bowl, combine and fork stir the flour, cinnamon & salt. Add to the mixer bowl and beat into the wet ingredients at medium speed. Continue mixing until a basic dough is formed, about 1 minute. Scrape down the bowl and paddle attachment. Cover the bowl with a damp tea towel and let the dough rest for 30 minutes.

After resting, replace the paddle with your dough hook. Knead the dough for 6-8 minutes on low speed. The dough will start off very sticky, and after kneading it will remain tacky, but should pull away from the bowl easily. If you find that this is not the case, add two or three tablespoons of AP flour and continue to knead.

Next, generously butter a medium sized mixing bowl. Scrape the dough off the dough hook and transfer to the bowl. Cover with a damp tea towel and again, rest for 30 minutes.

After this second resting, you will need to fold the dough. Grab one side of the dough in the bowl, stretch, and fold across to the center of the dough. Repeat on all four sides of the dough, stretching and pushing into the center. Turn the bowl as you go. This will help align the glutens in the dough, making it more silky.

Cover once finished, and let the dough rest at room temperature for 8-12 hours (I like to do this overnight), or until it has just about doubled in size.

After a good long ‘bulk rest’, you should have a soft and pliable dough.

After the bulk rest, you can roll, fill, and shape your dough. Flour a large wooden cutting board (or other hard surface for rolling), with AP flour. Gently transfer the dough from the bowl to your rolling surface. Stretch each side and gather into the center of the dough, as you did before the bulk rest the night before.

Flour your hands and gently flip the dough over, giving it a firm pat on the new surface side, and let rest for 15 minutes. This will allow time to relax the gluten.

Line a 9 inch springform pan with parchment paper (scrunch the paper into a ball, and then unfold & nestle into the pan).

Flour your hands (and rolling pin) lightly and roll the dough into a 16x12 inch rectangle. If the dough at any point becomes difficult to roll, don’t worry! Give it 10 minutes to relax and try again.

Take 1 cup of your wildberry jam, or favorite berry jam and spoon evenly over the rolled dough, leaving a 1/2 inch border untouched.

Starting from the long side, gently but firmly, begin to roll the dough. Slightly compress the roll as you go; you want a fairly tight roll when complete, to keep the jam from spilling out too much. End the roll with the seam side down on the board or counter.

Using a sharp knife or oiled bench scraper, cut the roll into 1 ½ inch rounds. You should get 7-8 rolls.

Gently place the rolls into the springform pan, making sure there is space around each to expand. Let the rolls rest and puff up. About 1-2 hours.

Preheat your oven to 350F. Once heated, place the pan on the middle shelf and bake for 40-45 minutes, or until puffed and golden brown.

After baking, cool in the pan for 15 minutes. Gently lift the rolls from the pan by gripping the parchment paper and transfer to a wire rack. Top with powdered sugar or lemon cream cheese frosting.