In the bowl of a stand mixer, combine the water, yeast, brown sugar, 2 tablespoons sriracha sauce, and flour. Using a dough hook, mix on low until the flour begins to combine. Increase the speed to medium and knead until a dough ball forms.
Let rise in a lightly greased bowl for 20 minutes. Meanwhile, preheat oven to 500 degrees.
Line a baking sheet with parchment paper or lightly spray with nonstick cooking spray. Fill a medium-size saucepan with water and stir in baking soda. Bring to a boil.
Pull off walnut-sized pieces of dough. Press a cheddar cheese cube into the center and pinch dough to seal the cheese inside, forming a ball. Repeat with remaining dough.
Working in batches, put dough balls into boiling water for 1 minute. Remove and place directly onto baking sheet.
Bake at 500 degrees for about 5 minutes, until dark brown.
Mix together melted butter and remaining 2 tablespoons of sriracha. Brush over hot pretzel bites.