Using a countertop mixer, add the flour, salt, brown sugar, yeast, and warm water; stir until well combined. Increase speed to medium and mix for 5-6 minutes.

Transfer dough to an oiled bowl. Cover and place in a warm (85°F) location for 30 minutes. (Note: I typically put the bowl in the oven. I turn the oven light on, but do not turn actual oven on.)

Meanwhile, combine the boiling water with the baking soda; mix until well combined. Set aside to cool.

Using a medium mixing bowl, add both cheeses; stir until well combined.

Spray an 11” or 12” cast iron skillet with nonstick baking spray.

Once dough has risen, divide into 16 equal pieces. Flatten each piece into a 3” square. Divide cheese mixture evenly into center of each square of dough. Carefully fold edges of the dough together and pinch to seal. (Note: Make sure seams are sealed or the cheese will melt out while baking.)

Using a circular motion, roll each piece of dough between countertop and palm of your hand until dough ball becomes tight.

Preheat oven to 475°F.

Place pretzel bites into baking soda/water mixture for 2 minutes (spoon water over the top of the pretzel if it is not fully covered by the water). Transfer pretzel bites into greased cast iron skillet. Sprinkle bites with coarse salt, and allow the pretzels to rest for 10 minutes uncovered.

Using a sharp knife, cut a small “x” into the top of each pretzel ball.

Bake at 475°F for 9-11 minutes, or until pretzels are golden brown in color. Remove pretzels from oven and brush with melted butter.