Heat the milk until it is lukewarm, stir in the yeast. Set aside to bloom for 10 minutes.
In a large stand mixing bowl, add flour and sugar, and whisk together.
Add in the remaining dough ingredients and the bloomed yeast/milk mixture.
Use the dough hook to knead the dough on medium low speed for 10-15 minutes until smooth.
Shape the dough into a ball and place in a lightly greased bowl.
Cover the bowl with plastic wrap or proofing bag and set it somewhere warm to rest for 1 hour.
Apple Filling
Peel and cut the apple into 1/4" chunks.
Add the cut apple into a bowl and squeeze the lemon juice over the top. Stir to combine.
Stir the cinnamon and sugar together to create the cinnamon sugar mixture.
Assembling the Schnecken
Prepare two baking sheets with parchment paper or silicone baking mats.
After the 1 hr has passed, roll the dough out into a rectangle that measures 24 x 45 cm.
Spread the softened butter over the dough.
Add 2-3 tablespoons of the cinnamon sugar mixture to the chopped apple and stir to combine.
Spring the apple filling over the spread butter.
Roll up the dough starting with one short side. As you roll, squeeze it to make sure the roll is nice and tight.
Measure out slices that are approximately 2 cm thick. Then cut at each 2 cm mark. Place the slices onto the baking sheets, leaving at least 3 inches between each roll. There should be no more than 6 on a half size baking sheet.
Tuck the ends under each roll. Leave the schnecken to rest for 30 minutes
Preheat the oven to 350 F or 325 F if baking on convection.
Baking and finishing
After the schnecken have rested for 30 minutes, bake them for 20 min until golden brown. Rotate and switch the baking sheets after the first 12 min to ensure even browning if not baking on convection.
Once the schnecken are done baking, while still hot, brush with the melted butter.
Sprinkle all of the schnecken with the remaining cinnamon sugar. Leave to cool for at least 5 minutes before enjoying.
Notes
These will last for a few days in an airtight container at room temperature!