Prove the yeast
Combine the warm water and brown sugar in the bowl of a stand mixer fitted with the dough hook. Sprinkle the yeast on top and let it sit until it begins to foam.
A sturdy brown-sugar dough, rolled into ropes, twisted, and boiled in baking-soda water before it ever sees the oven. That boil is what makes the crust.
Weigh everything
This one is written in grams rather than cups, and it is better for it — pretzel dough is stiff enough that a cup of flour either way changes the result. A scale is worth getting out.
Combine the warm water and brown sugar in the bowl of a stand mixer fitted with the dough hook. Sprinkle the yeast on top and let it sit until it begins to foam.
Add the sourdough discard, flour and salt, and mix on low speed. While the mixer is running, pour in the melted butter and mix until combined. Change to medium speed and keep kneading until a smooth dough forms. If it needs it, add more flour or water a spoonful at a time.
This dough should be fairly sturdy, smooth and not sticky — nothing like the focaccia. That firmness is what lets you roll ropes.
Transfer the dough in a ball to a large, oiled bowl. Cover with plastic wrap and let it sit until doubled in size.
Line two half-sheet baking trays with parchment paper or a baking mat. Turn the dough out onto a smooth, dry work surface — no flour and no oil, you want some traction. Divide it into eight equal pieces and roll each one into a long rope. Make a U-shape with the rope, roll the ends over each other like a heart, twist them together and push the twist down at the bottom of the U. Place them on the trays and cover with plastic wrap or a clean towel while you prepare the next step.
Preheat the oven to 230°C. Bring the water and baking soda to a boil in a large pot.
Add the baking soda to the water before it boils. Adding it to boiling water gives you a bubbly mess across the hob.
Place the pretzels in the boiling water one by one, twenty to thirty seconds on each side — a longer boil makes a thicker crust. Remove them with a slotted spatula, shake off the excess water and return them to the baking sheet. Lightly brush each one with the egg wash and sprinkle with flaky sea salt.
The pretzels should float. If they sink, cover the unboiled ones and let them rise another ten minutes, then try again — sinking means they have not risen long enough and will bake dense.
Bake until golden brown, then transfer to a cooling rack to cool fully. Serve with your favourite dipping sauce.
For pretzel bites, roll each section of dough into a rope as usual, then cut it into short pieces and carry on from there. For mini pretzels, divide the dough into three times as many pieces and shape them the same way. For cinnamon sugar pretzels, leave out the egg wash and the flaky salt; bake as directed, let them cool, then brush them with melted butter and sprinkle with sugar stirred together with ground cinnamon.
You do not need a stand mixer for any of this — a large bowl, a wooden spoon and your hands work. Active starter can replace the discard weight for weight; leave the yeast out and give the rises longer.