Combine warm water, sugar, salt, and yeast in the bowl of a stand mixer. Allow the mixture to rest for 5–10 minutes until it becomes frothy.
Add the melted butter and 2 cups of flour to the yeast mixture. Use the dough hook attachment on low speed to combine the ingredients, gradually incorporating the remaining flour until the dough forms.
Knead the dough with the dough hook for approximately 5 minutes, or knead by hand on a floured surface for about 10 minutes, until the dough achieves a smooth texture.
Transfer the dough to a lightly oiled bowl, covering it securely. Let it rise in a warm environment for 1 hour, or until its volume doubles.
Preheat your oven to 450°F and prepare baking sheets by lining them with parchment paper. In a large pot, bring the water and baking soda to a boil.
Divide the risen dough into 8 equal portions. Roll each piece into a 24-inch rope, then form each rope into a pretzel shape by creating a "U," crossing the ends over one another, and folding them down to the base of the "U."
Using a large spatula, carefully immerse each pretzel into the boiling water bath for 10–15 seconds. Remove from the water, allowing excess liquid to drip off, and arrange the pretzels on the prepared baking sheets with at least 2 inches of space between them.
Brush each pretzel with the beaten egg yolk mixture and sprinkle with kosher salt, or any toppings of choice.
Bake in the preheated oven for 12–14 minutes until the pretzels turn a deep golden brown.
Enjoy these warm, soft pretzels fresh from the oven!