1. Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
2. In a shallow dish, combine flour, Pecorino Romano, lemon zest, garlic powder, salt, and pepper.
3. Dredge each chicken breast in the flour mixture, pressing to coat evenly.
4. Arrange the coated chicken breasts on the prepared baking sheet.
5. Bake for 20-25 minutes, or until chicken is cooked through and the crust is golden brown.

Make the Creamy Lemon Sauce:

1. While the chicken is baking, melt butter in a saucepan over medium heat.
2. Whisk in flour and cook for 1 minute, stirring constantly.
3. Gradually whisk in chicken broth until smooth.
4. Bring to a simmer, stirring constantly, and cook for 2-3 minutes, or until thickened.
5. Stir in heavy cream, lemon juice, lemon zest, salt, and pepper.
6. Reduce heat to low and simmer for 5 minutes, or until the sauce is smooth and slightly thickened.

Assemble and Serve:

1. Once the chicken is cooked, pour the creamy lemon sauce over the chicken breasts.
2. Serve immediately.