They are best right out of the oven (with plenty of mustard, of course), but as my husband discovered, cold ones are easy to reheat in the toaster.
(adapted from Home Baking by Jeffrey Alford and Naomi Duguid)
1 cup milk, scalded and cooled to lukewarm
1 envelope active dry yeast
1 tbsp honey
1 cup bread flour
1 1/4 to 2 cups all purpose flour
1 tsp salt
2 tbsp unsalted butter, softened
1/4 cup baking soda
1 egg yolk
2 tsp milk
Place the scalded milk in the bowl of a stand mixer, and stir the yeast in until dissolved.
Add the honey and one bread flour, and stir until smooth.
Sprinkle on the salt, add the butter, and stir well to incorporate.
Add 1 1/4 cups all purpose flour, and mix with the dough hook for about 5 minutes, until dough is smooth. Add a little more flour if the dough is too sticky.
Transfer to a clean bowl, cover with plastic wrap, and let rise until doubled in bulk, about 1/5 hours.
Preheat the oven to 450 F.
Turn the dough out onto a floured surface and cut into 8 equal pieces.
Roll each piece out into a long skinny rope, 24-30" long. Pick up the ends, twist, and press into a typical pretzel shape.
Let the pretzels rise for about 10 minutes under a clean kitchen towel while you boil 1 cup of water with the baking soda in a small saucepan (make sure one pretzel at a time will fit in the pan!)
Mix together the egg yolk and milk.
Carefully lift a pretzel with a spatula and place in the boiling water. After 20 seconds, remove and shake off the water. Place on a Silpat or parchment-lined baking sheet and repeat with the remaining pretzels.
Brush the egg yolk-milk mixture over the pretzels, then sprinkle with kosher salt.
Bake for about 12 minutes, or until deeply golden brown, then cool on a wire rack.