In the bowl of a Stand Mixer (or a large Mixing Bowl), combine the 1 ½ cups agua tibia 110°F — tibia al tacto pero no caliente, 2 ¼ tsp levadura seca activa un paquete estándar, and 1 tbsp azúcar granulada. Stir gently and let sit for 5–8 minutes until the mixture looks foamy and active. If it doesn't foam, your 2 ¼ tsp levadura seca activa un paquete estándar may be old — start over with fresh 2 ¼ tsp levadura seca activa un paquete estándar.

Add the melted 2 tbsp mantequilla sin sal derretida y ligeramente enfriada and 1 tsp sal fina to the 2 ¼ tsp levadura seca activa un paquete estándar mixture. Add the 4 cups harina de trigo común más para espolvorear one cup at a time, mixing with the dough hook on medium-low speed (or stirring with a Wooden Spoon) until a shaggy dough forms.

Knead the dough with the dough hook on medium speed for 5 minutes, until smooth and elastic. The dough should pull away cleanly from the sides of the Mixing Bowl. If it's sticky, add 4 cups harina de trigo común más para espolvorear one tablespoon at a time. If kneading by hand, knead on a lightly floured surface for 8–10 minutes.

Shape the dough into a ball and place it in a lightly oiled bowl. Cover with a clean kitchen towel or Plastic Wrap and let rise in a warm spot for 45–60 minutes, or until doubled in size.

Once risen, punch the dough down and turn it out onto a lightly floured surface. Divide it into 8 equal pieces using a Bench Scraper or Knife.

Roll each piece into a long rope about 22–24 inches long. Work from the center outward with your palms, keeping even pressure. Form each rope into a U-shape, cross the two ends over each other twice, then fold the twisted ends down and press them firmly onto the bottom of the U to create the classic pretzel shape. Place shaped pretzels on Parchment Paper-lined Baking Sheet.

Preheat your Oven to 450°F. In a large wide Pot, bring the 10 cups of 1 ½ cups agua tibia 110°F — tibia al tacto pero no caliente to a boil. Carefully add the ⅔ cup bicarbonato de sodio — it will bubble up vigorously, so add it slowly. Reduce to a steady simmer.

Working one or two at a time, gently lower each pretzel into the simmering ⅔ cup bicarbonato de sodio bath using a Slotted Spoon or Spatula. Poach for exactly 30 seconds per side (1 minute total), then lift out, let excess 1 ½ cups agua tibia 110°F — tibia al tacto pero no caliente drip off, and return to the Parchment Paper-lined Baking Sheet. This step is what gives soft pretzels their chewy crust and deep brown color.

Whisk the 1 large huevo batido con 1 tbsp agua para el glaseado con huevo and 1 tablespoon of 1 ½ cups agua tibia 110°F — tibia al tacto pero no caliente together in a small Mixing Bowl to make the egg wash. Brush each poached pretzel generously with the egg wash, then immediately sprinkle with 2 tbsp sal de pretzel gruesa.

Bake the pretzels at 450°F for 12–15 minutes, until they are a deep mahogany brown. Rotate the Baking Sheet halfway through for even browning.

As soon as the pretzels come out of the Oven, brush them generously with the melted 2 tbsp mantequilla sin sal derretida y ligeramente enfriada. Serve warm with mustard, cheese sauce, or your favorite dip.