Try genuine stove paint, the stuff used to paint wood stoves. The BBQ paint sold at the hardware store won't last very long. If the steel stove top is galvanized, I'd suggest to have a fabricator make e new one. Stainless steel would be my choice. The cost of primer and paint, along with etching the galvanized surface is probably going to be more than fabrication.
FWIW, when I painted mine, I used the texture spray in a can. It still looks good but I haven't used the stove much. I'm pretty sure once I set a big pot on there with full heat, the paint will blister right off.
