Activate the yeast by combining warm water and sugar in a small bowl. Sprinkle the yeast over the top and let sit for 5–10 minutes until foamy.

Make the dough by combining flour, salt, softened butter, egg, and the activated yeast mixture in a stand mixer. Knead for 8–10 minutes until the dough is smooth and elastic.

Transfer the dough to a greased bowl, cover with a clean towel, and let rise in a warm place for 1 to 1½ hours until doubled in size.

Once risen, divide the dough into 4 equal portions. Working with one at a time, roll each piece into a long, thin rectangle (about 12×6 inches).

Spread softened butter over the surface of each rectangle. Roll up tightly from the long side into a log.

Slice each log in half lengthwise using a sharp knife or bench scraper. You should now have 8 halves.

Shape each cruffin by rolling each sliced half into a spiral, cut-side out, and tucking the end underneath. Place each spiral into a greased muffin tin.

Cover loosely and let rise for 30–45 minutes until puffy. Preheat your oven to 375°F during the final rise.

Bake for 18–22 minutes or until golden brown and cooked through. Remove and cool in the tin for 5 minutes before transferring to a wire rack.

Once cooled, dust with sugar or pipe in your favorite filling using a pastry bag if desired.