Start by making your rye starter from the recipe at the bottom.

Once you have made your rye starter and are ready to bake your buns, you need to feed it using the Starter ingredients above.

In a medium bowl, use your hands to mix the water, flour and the 12-hour starter you have made for a minute or so.

Take this mixture's temperature. At this point, it should be about 30°–35°C.

Scrape the excess mixture off your fingers back into the bowl, then rinse your hands in the bowl of warm water.

Now, use your plastic scraper to push the starter mix together, getting everything off the insides of the bowl and into one cohesive body.

Cover the bowl with a tea towel and leave the freshly fed starter in a warm, draft-free place. Set a timer for 45 minutes.

Once the starter is ready, it’s time to make your dough.

In the bowl of a stand mixer fitted with the dough hook, combine both flours, the sugar, milk powder, eggs, water and starter and mix on medium speed to combine.

Let it rest for 30 minutes.

Add the salt and yeast and mix the dough thoroughly on medium speed until it is completely smooth and very strong, around 10 minutes.

Now add half (38.5g) of the butter and mix the dough until it is fully incorporated.

Add the remaining butter and mix again until it is fully incorporated.

Now add the oil, half at a time. Allow the first half to be completely absorbed before adding the rest.

Transfer the dough to an oiled container large enough to hold double its size and allow it to bulk ferment at room temperature for 45 minutes to 1 hour.

Cover with a tea towel and refrigerate overnight, up to 12 hours.

Meanwhile, make the cinnamon sugar. In a bowl or other container, combine the sugar, cinnamon and salt and mix well.

The next day, once the dough has been bulk fermented, make the cinnamon schmear.

Turn the chilled dough out onto your work surface.

Using a palette knife, small spatula, or butter knife, spread the schmear in an even layer over the dough.

With a long side of the rectangle facing you, roll it into a long log, starting from the top edge and rolling tightly to avoid leaving any air pockets.

Transfer the log to the fridge to chill for 30 minutes.

Use the pastry brush to brush the insides of the cake pan or baking dish with the softened butter.

Remove the log from the fridge and use a sharp knife to cut it crosswise into 8 equal-sized pieces.

Arrange the pieces in the prepared pan, leaving 1cm space between them.

Let the buns proof in a warm place for 1 hour.

Preheat the oven to 185°C.

Bake the buns for 15 to 17 minutes, until they are deep golden brown and the internal temperature is at least 98°C.

While they are still warm from the oven, invert the buns onto a cooling rack.