In the bowl of a stand mixer, combine the yeast, sugar, flour and salt.
Add the softened butter, then add the hot water gradually to the flour mixture, stirring until well mixed.
Attach the dough hook and knead for about 8 minutes. If dough is too dry as it kneads, add a tiny bit of water. If it is too wet, add a little flour.
Transfer dough to an oiled bowl and turn so that dough is lightly coated with oil. Cover and let rise for one hour.
After dough has risen, divide it into 10 pieces.
Preheat the oven to 450 degrees F.
Bring the water and baking soda to a boil in a large saucepan.
Roll out each piece of dough into a 24-inch rope and shape into a pretzel shape directly on nonstick foil or parchment lined baking sheet.
Working one piece at a time, put the shaped pretzel in the boiling water for 30 seconds, then lift it out with a slotted spatula and return to lined baking sheet.
When all pretzels are formed, brush with the egg yolk mixture and sprinkle with salt.
Bake for about 12-14 minutes at 450.