Sift the flour into a bowl, make a well in the center and add in the sugar, vanilla sugar and cinnamon. Crumble the yeast and mix it with 3-4 tablespoons of lukewarm milk. Add to the bowl and mix all well. Cover the bowl and let the dough rest in a warm place for about 15 minutes.
Add the eggs and the softened butter. Knead well while gradually adding the rest of the milk. Knead until the dough becomes smooth and does not stick to the bowl's sides. If needed, you can use a little more milk or flour. Cover and leave the dough to rest again for about 45 minutes.
Preheat the oven to 200°C (approximately 400°F). Line a baking sheet with parchment paper.
Divide the dough into 8-10 equal pieces and knead each piece. Shape the pieces into strands of about 18 cm (approximately 7 inches) in length and merge the corners of each strand to form a ring. Press the ends together well. Sprinkle a little flour on top and cut stripes all the way around into each dough ring. With your hands, slightly pull apart each stripe so a fine pattern emerges. Place the dough on the baking sheet and bake until golden brown for about 30 minutes. Cool on a wire rack and serve.