Mix together flour, yeast, sugar, salt, and warm water until the dough starts to come together. It will by a little dry since the butter hasn't been added.
Knead in the butter until you have nice smooth dough. Let rise in a warm place until the size about doubles.
Punch dough the dough and separate into 2 to 3 equal balls. Roll out dough into long rolls so you can shape them into pretzels. Feel free to make any shape you wish, though, such as, rolls or crescents.
While the dough rises a little longer, boil the 750 ml of water with baking soda. When it comes to a boil, drop in each pretzel for about 1 minute (30 seconds on each side).
Pull out boiled pretzels and let the sit for a few minutes.
Bake in oven for about 20 minutes, or until they brown. Sprinkle rock salt on top once finished!