Mix all ingredients well and knead until smooth, elastic, and passes the window pane test (may want to link or explain what that is)
Place in a covered bowl and allow to rest overnight or for 8-12 hours at room temperature
Turn dough out onto a clean work surface and divide into about 8 equal pieces
Using your hands, gently roll out each piece of dough to create a long rope shape about as thick as your thumb
Form the snake of dough into a pretzel by following the above images or by watching the linked video.
Cover dough and allow to rise for about an hour or until very puffy.
When your dough is almost done rising, bring a heavy bottomed pot to boil adding the baking soda and brown sugar.
Preheat the oven to 425 degrees F
Boil all of the pretzels for about 30 seconds and place on a lined baking sheet
Mix the egg wash and brush on each pretzel.
Add kosher salt, or your own topping of choice
Bake for 15 minutes or until golden
Notes
Sourdough soft pretzels can be stored for a few days in a sealed container at room temperature. Or a week or so in the refrigerator. They also last in the freezer for a few months and can be easily reheated in the toaster.