In a pan over medium-high heat, add enough oil to coat the bottom of your pan.
On a plate or in a container, add flour, onion powder, garlic powder, salt, pepper, and rosemary. Crush the dried rosemary leaves between your fingers to break them into small bits and release the flavor. Mix together until evenly distributed.
Butterfly chicken into thin cutlets. If they're thick, I usually cut them in half, and then optionally can gently pound them to be even flatter. Dredge in flour mixture by adding to the mixture and shaking and turning to coat.
Add chicken to pan and cook for 2-4 minutes on each side, until cooked through and crisp on the outside. Set aside on a towel to drain.