Combine water, sugar and kosher salt in the bowl of a stand mixer. Sprinkle yeast on top. Allow to sit for 5-10 minutes or until the mixture begins to foam.
To the bowl, add flour and butter. Using the dough hook attachment, mix on low speed until well combined. Change to medium speed and knead until the dough is smooth and pulls away from the side of the bowl, about 4-5 minutes.
Remove dough from bowl, clean bowl and oil bottom and sides with vegetable oil. Return dough to bowl. Cover with plastic wrap and allow to sit in a warm place for approximately 50-60 minutes or until the dough has doubled in size.
Preheat the oven to 450°F. Line 2 large sheet pans with parchment paper and lightly brush with vegetable oil. Set aside.
In an 8 quart saucepan or pot, bring 10 cups of water and baking soda to a rolling boil.
Meanwhile, turn dough out onto a slightly oiled work surface and divide into 8 equal pieces. Roll out each piece of dough into a 24-inch rope. Make a U-shape with the rope, holding the ends of the rope, cross them over each other and press onto the bottom of the U in order to form the shape of a pretzel. Place onto parchment-lined sheet pan.
Place the pretzels into the boiling water, one at a time for 30 seconds each. Remove them from the water using a large flat spatula.
Return to sheet pan, brush the top of each pretzel with beaten egg yolk and water mixture. Sprinkle with salt. Bake until dark golden brown in color, around 12-14 minutes.
Transfer to a cooling rack for at least 5 minutes before serving with mustard or cheese sauce for dipping..