Mix sourdough starter, flour, water, brown sugar, molasses and salt in mixer for 5 minutes. Add the dough ball to a large greased bowl, cover bowl with a shower cap and ferment 6-12 hours until doubled in size. *Warm the oven for a few seconds or leave the light on in the oven to ferment in there if you can. The little bit of warmth helps with the fermentation.
Divide the dough into 12 even pieces. *I prefer to use a scale to keep them even but it's not necessary.
Roll out each ball into a skinny 2 foot line. Grab and lift both dough ends and flip the dough around in a forward circle in the air several times to help stretch it out. Then REST dough in straight line for 5 minutes. *This rest is vital so the pretzels hold their shape!
Shaping pretzels: Take the 2 dough ends and make a wide horseshoe shape on your counter so the "U" shape is face up. Twist the two ends twice to resemble a "Jesus fish" leaving a 2 inch tail near the ends after the twist. Then take the two ends and fold them down onto the bottom of the "U". It should look like a pretzel now. *Refer to the pictures in this post for visual reference.
Place shaped pretzels on 2 parchment lined cookie sheets. *I am able to fit 6 on each cookie sheet.
Proof pretzels for 1 hour in a slightly warmed oven until they're nice and puffy. *proof longer if necessary
Preheat oven to 425 degrees F.
Boil 2 quarts of water in a large pot on stovetop. Once water is a rolling boil, add in 2 tablespoons of brown sugar and 1 tablespoon of baking soda.
Carefully lift each pretzel (so as not to deflate) and drop pretzels 2-3 at a time into boiling water. Boil them on each side for 30 seconds. *They will get nice and puffy so don't overcrowd them in the water, 2 or 3 at a time, max!
Remove pretzels with a spider strainer and blot on a towel to remove excess water. Add them back to the parchment lined cookie sheet. Continue this process until all pretzels have been boiled.
Two Options: Brush pretzels with egg wash and sprinkle with coarse sea salt. OR (my favorite) brush pretzels with melted butter and sprinkle with coarse sea salt.
Bake pretzels at 425 degrees F for 10 minutes or until golden brown.