Roll/spread the softened butter into an 8x6 inch (15x20 cm) rectangle on a piece of parchment paper.
Cover it with another piece of parchment paper and place it in the refrigerator for about half-hour or until it’s starting to firm up.
Meanwhile, in a stand mixer or a big mixing bowl, combine the flour, yeast, sugar, and salt.
Then add the egg, milk, and vanilla extract and knead until it becomes a smooth dough.
Roll out the dough into a 9x13 inch (22x32cm) rectangle with a rolling pin. Take the previously spread-out butter out of the refrigerator, place it on one half of the dough and fold the other dough half over the butter to cover it completely. Tuck in the edges, so the butter doesn’t get pressed out of the dough when rolling it with the rolling pin.
Laminating Step 1*: Carefully roll the dough into a 9x13 inch (22x32cm) rectangle again. Next, fold the dough into thirds by folding the top short side one-third over and then take the bottom third of the dough and fold it onto the top already folded side.
Cover the dough with plastic foil and place it in the refrigerator for at least half an hour before rolling out and folding again. That time in the fridge helps the gluten relax and the butter firm up again, making the rolling out easier.
Repeat Step 1* two more times, and let the dough rest between each folding step for at least 30 minutes.
Cut the dough in half and wrap them individually in plastic foil, and place them in the refrigerator until chilled completely. For this recipe, I only used one-half of the dough. Unless you have to feed a big crowd, you can freeze the other half and use it another time.