How to Make It
Let dough stand for 1 hour at room temperature in package.
Preheat oven to 450°F. Bring water to a boil in a large stockpot over high. While water is heating, turn dough out onto a lightly floured surface; divide dough into 4 equal pieces. Roll 1 dough piece into about a 30-inch rope. Holding 1 end of the dough rope in each hand, make a U-shape on floured surface. Leaving about a 3-inch tail on each end, cross the dough ends. Cross the ends again, twisting them together much like a twist tie. Bring the 3-inch tails down, and attach to dough under bottom of U-shape (1 end at about 5 o'clock and the other at about 7 o'clock), forming the shape of a pretzel. Repeat procedure with remaining 3 dough pieces.
Add soda to boiling water; stir until soda dissolves. Add 1 dough pretzel to boiling liquid, and cook 1 minute. Transfer boiled pretzel to a lightly greased wire rack over a rimmed baking sheet. Repeat procedure with remaining 3 dough pretzels, making sure to return cooking liquid to a boil before adding another dough pretzel. Let pretzels drain until mostly dry, about 10 minutes.
Brush pretzels with melted butter; sprinkle with salt. Bake in preheated oven until a deep golden brown, about 8 minutes. Turn pretzels, and bake until a deep golden brown, about 5 minutes. Let cool 5 minutes before serving. Serve with yellow mustard.