Add brown sugar, butter and yeast warm water to a large bowl. Let the yeast soften in the mixture for about 3 minutes;
Add flour to the mixture of yeast and water, and use the hook attachment of the mixer to mix for 3 minutes until it is smooth, elastic and a little sticky;
Cover the dough with a kitchen towel and let it rise for one hour;
Divide the dough into 8 equal balls. Place them on the greased basket and wait for 20 to 30 minutes;
Boil 8 to 10 cups of water in a large pot, then add baking soda. Stir and put the water back to a boil. Add the pretzel balls to the water one at a time. Boil for 30 seconds, then flip the ball with a colander and boil on the other side for 30 seconds. This will be the tub where the grilled pretzel is cooked before baking. This step makes the bread show a beautiful dark color and unique flavor;
Then use a slotted spoon to remove it from the water and place it on a frying basket lined with parchment paper. Brush the top of the dough ball with egg wash. Using a very sharp knife, cross the top of each pretzel bowl. Sprinkle with salt;
Bake in an air fryer preheated at 400°F for 10 to 15 minutes, or until dark brown and crusty. The middle can be pulled out to view the effect.