In a mixing bowl, combine the active sourdough discard, 2 tablespoons of the melted butter, and warm water. Stir gently until the mixture is well combined.

In a separate bowl, mix the flour, 1 teaspoon of salt, and instant yeast, if using. Whisk until evenly blended.

Gradually add the dry mixture into the wet ingredients. Stir with a spatula until a shaggy dough begins to form.

Turn the dough out onto a lightly floured surface and knead it for about 5 to 7 minutes until smooth and elastic.

Place the kneaded dough into a lightly greased bowl. Cover it and let it rise in a warm area until it doubles in size (60 to 90 minutes).

Once risen, preheat your oven to 425°F and prepare a baking sheet with parchment paper.

Gently deflate the dough and divide it into 8 equal pieces. Roll each piece into a long rope, about 24 inches in length.

Shape each rope into a pretzel form by twisting the ends and folding them back toward the center.

Bring a large saucepan of water to a boil. Add the baking soda and stir. Carefully place pretzels into the boiling water for about 30 seconds.

Using a slotted spatula, transfer the pretzels to the prepared baking sheet. Brush the tops with egg white and sprinkle with coarse sea salt.

Bake the pretzels for 12 to 15 minutes or until golden brown.

Let them cool on a wire rack for a few minutes before serving.