Proof yeast: Place the lukewarm water, yeast, and sugar in the bowl of the stand mixer fitted with a dough hook. Stir and let the yeast proof for about 10 minutes; the mixture should become bubbly.
Combine: Add the milk and about 1/3 of the flour. Stir with a spoon. Let rest for 5 minutes. Add the remaining flour, salt, eggs, and oil.
Knead with the dough hook on low speed until the dough is smooth and elastic.
Let rise: Cover the bowl with a clean kitchen cloth and let the dough rise in a warm place for about 2 hours; it should double in size.
Melt the butter in a small pan. Use a small amount of melted butter to brush a large baking dish of about 30x20 cm/ 12x8 inches.
Cinnamon sugar: In a small bowl, mix the brown sugar and the cinnamon.
Roll the dough to a rectangle of about 40x50 cm/ 16x20 inches on a floured surface. Brush the surface of the dough rectangle with the melted butter. Sprinkle it evenly with ¾ of the sugar-cinnamon mixture.
Cut rolls: Roll the dough starting at one of the shorter ends. Cut the dough into 12 thick slices of about 3.5 cm/ 1.5 inches each. Place the sweet rolls in the prepared baking dish. Sprinkle with the remaining cinnamon sugar.
Let rise: Cover with the cloth and let rise in a warm place for about 20 minutes.
Bake: In the meantime, preheat the oven to 200 degrees Celsius/ 400 degrees Fahrenheit. Bake the cinnamon rolls for about 20 minutes until golden and cooked through. Serve preferably warm.