Bloom yeast in warm water with 1 tbsp brown sugar for 5-10 minutes until foamy. Mix with remaining brown sugar, melted butter, flour, garlic powder, and Celtic Kosher™ and knead until smooth and elastic. Cover and let rise 1-2 hours until doubled. Divide into 8 pieces, roll into ropes, shape pretzels, and rest 30 minutes. Bring 9 cups water and baking soda to a boil. Boil pretzels for 30 seconds per side, transfer to a lined baking sheet, brush with egg yolk, sprinkle with pretzel salt, and bake at 450°F for 10-12 minutes until deep golden. Mix melted butter, garlic, Celtic Kosher™, garlic powder, parsley, and parmesan, then brush over warm pretzels. For the cheese sauce, melt butter in a saucepan, whisk in flour, slowly whisk in milk until thickened, then stir in cheddar and Celtic Kosher™ until smooth. Serve warm.
