In a large mixing bowl, combine all-purpose flour, warm water, active dry yeast, brown sugar, and salt to form a dough. Knead for about 5 minutes until smooth and elastic. Cover and let rise for 1 hour.

After the dough has risen, punch it down and divide into small pieces. Roll into ropes and twist into pretzel shapes or cut into bite-sized pieces. Arrange on a parchment-lined baking sheet and let rest for 15 minutes.

Preheat oven to 425°F (220°C). In a large pot, boil water and add baking soda. Drop pretzel bites into boiling water for 30 seconds, then remove with a slotted spoon and transfer back to the baking sheet.

Bake pretzel bites for 12-15 minutes or until golden brown. Let cool on a wire rack.

In a medium saucepan, melt unsalted butter over medium heat. Whisk in all-purpose flour and cook for 1-2 minutes until bubbly. This is the roux.

Gradually add whole milk, whisking to prevent lumps. Cook until the sauce thickens, then lower heat and stir in shredded cheddar cheese until melted.

Season the cheese sauce with garlic powder, mustard powder, salt, and pepper to taste. Stir well and adjust seasonings as necessary.

Serve warm soft pretzel bites alongside the cheddar cheese sauce for dipping.