The night before, prepare the preferment by mixing 1 tablespoon flour (10 grams), 1 teaspoon water (5 ml), and 1/4 teaspoon fresh yeast (1 gram). If you have a sourdough starter, you don't need to make the preferment.

In a bowl, add the egg and sugar. Whisk until the sugar dissolves. Add the sourdough starter (or preferment) and the yeast dissolved in a little warm water. Then add the remaining water.

Gradually add the flour, mixing until everything is well combined. Knead the dough in the bowl for a few minutes, then let it rest for about 5 minutes.

Transfer the dough to a lightly oiled countertop and knead for a few minutes. Let it rest for 10 minutes. Repeat this kneading and resting process until the dough is smooth.

Once the dough is ready, cover and let it rest for about 30 minutes.

After 30 minutes, the dough will have relaxed and is ready to be rolled out. Divide it into 4 equal pieces and shape each into a ball.

Take one piece of dough and roll it out with a rolling pin into a roughly rectangular shape.

Spread plenty of butter over the dough using your hands. Now stretch the dough as thin as possible.

Roll the dough up tightly to form a rope. Let it rest for about 20 minutes, then gently stretch it a bit more, being careful not to tear it.

Shape the rope into a spiral and place it on a greased baking sheet or parchment paper. Repeat with the remaining 3 pieces of dough.

Let the spirals rise overnight in the turned-off oven (12 hours or more). By the next day, the ensaimadas should be nicely puffed up.

Bake at 340–355°F (170–180°C), with both top and bottom heat and no fan, for about 15 minutes. Watch closely so they don't overbake.

Once the ensaimadas have cooled, dust them with powdered sugar.