In a large mixing bowl, combine the warm water, sugar, and yeast. Stir gently and let it sit for 5 minutes until it becomes frothy. This step is crucial as it ensures your pretzels will rise properly.
Once the yeast is activated, add the flour and salt to the bowl. Mix until a dough forms. You can use a stand mixer with a dough hook or knead by hand for about 5-7 minutes until the dough is smooth and elastic.
Cover the dough with a clean kitchen towel and let it rise in a warm place for about 1 hour, or until it doubles in size.
While the dough is rising, preheat your air fryer to 375°F. Preheating ensures that your pretzels cook evenly.
Once the dough has risen, punch it down and divide it into 8 equal pieces. Roll each piece into a long rope (about 20 inches) and then shape it into a pretzel. To do this, form a "U" shape with the dough, then cross the ends over each other and press them onto the bottom of the "U".
In a large pot, bring 5 cups of water to a boil. Add the baking soda and stir until dissolved. Carefully dip each pretzel into the baking soda bath for 30 seconds. This step helps give the pretzels their characteristic golden-brown color and chewy texture.
Place the pretzels in the air fryer basket, making sure not to overcrowd them. Prepare the egg wash for the pretzel. Mix the egg yolk and water. Brush each pretzel with egg wash or brush with melted butter and sprinkle with coarse sea salt. Air fry at 375°F for 7-9 minutes, or until the pretzels are golden brown and cooked through.
Once your pretzels are done, remove them from the air fryer and let them cool slightly before serving. Enjoy them plain, or with your favorite dipping sauce!