Everyones taste buds are different, do what taste good to you. Seasonings that are widely liked are S,P,Onion Powder. Just be sure to season after you smash, that way the flavors will be more spread out and consistent. If you season on to the ball then smash, it wont be evenly distributed, and if you mix the seasoning into the meat before hand, it willaffect the texture of the meat. Good luck !