Mix the dough. In a stand mixer fitted with the dough hook, combine the flour, 1/4 cup sugar and salt. Add the eggs and the yeast mixture. Mix on low until a shaggy dough forms.

Add the butter. With the mixer running, add the butter one piece at a time, letting each blend in before adding the next. Increase to medium and knead 10 to 12 minutes, until smooth and pulling away from the bowl. Add flour a tablespoon at a time if it still clings.

First rise. Transfer to a greased bowl, brush lightly with oil and cover. Heat the oven to 170°F, turn the oven off, and let the dough rise inside for 1 hour.

Chill. Refrigerate the dough 3 to 4 hours or overnight.

Make the filling. In a heatproof bowl over barely simmering water, melt the salted butter and chocolate, stirring constantly. Remove from the heat and whisk in the powdered sugar and cocoa powder. Cool until spreadable.

Roll and fill. Press the air out of the dough and divide into 4 pieces. Roll one piece into a rectangle about 8 by 10 inches. Spread with a quarter of the filling, leaving a 1-inch bare strip along one long edge. Brush the strip with water.

Roll up. Starting at the filled long edge, roll tightly toward the wet edge and pinch the seam to seal. Cut the log in half crosswise.

Twist and knot. Slice each short log in half lengthwise, leaving the top inch attached. Twist the strands, cut sides up. Curl into a circle, tuck the end through the center and pinch to seal. Place on parchment.

Repeat with the remaining dough and filling for 8 knots.

Second rise. Cover with a towel and let rise 1 to 2 hours, until puffy.

Egg wash. Beat the egg and water together and brush over the knots.

Air fry. Place 2 to 4 knots in the basket on their parchment, not touching. Air fry at 300°F for 15 to 18 minutes, until deep golden and 190°F inside. Repeat with the remaining knots.

Cool at least 10 minutes before serving.