Preheat oven to 400°F (200°C) if baking. Set up a wire rack over a baking sheet and spray with cooking spray.

Place crushed pretzels in a shallow dish. In a separate dish, combine flour, garlic powder, onion powder, paprika, salt, and pepper.

Pat chicken breasts dry with paper towels. Dredge each breast in the seasoned flour mixture, shaking off excess. Dip in whisked eggs, allowing excess to drip off. Press firmly into crushed pretzels, ensuring an even coating on all sides.

Option 1 (Pan-Fry): Heat olive oil in a cast iron skillet over medium-high heat. Cook chicken 4-6 minutes per side until golden brown and internal temperature reaches 165°F (74°C). Option 2 (Bake): Place coated chicken on prepared wire rack and bake 18-25 minutes, flipping halfway, until golden and cooked through.

Transfer chicken to a clean wire rack to rest while preparing the sauce. This prevents the bottom from steaming and maintains crispiness.

In a small saucepan over medium heat, melt butter. Whisk in flour and cook 1 minute until fragrant and lightly golden.

Gradually whisk in milk, ensuring no lumps form. Cook 3-5 minutes, stirring constantly, until sauce thickens and coats the back of a spoon.

Remove from heat and stir in shredded cheddar until melted and smooth. Add Dijon mustard, whole grain mustard, cayenne (if using), salt, and pepper. Adjust seasoning to taste.

Serve chicken hot with mustard-cheddar sauce drizzled over or on the side. Enjoy immediately for maximum crispiness!