Heat transfer in steak is just a diffusion problem, basically a 1‑D conduction equation with a boundary condition at the grill surface. I’ve already built a spreadsheet that plots T versus depth over time for a 1‑inch slab at 550°F. If you want a quick reference, set up columns for time (s), depth (mm), and temperature, then use the analytical solution: T(x,t)=T₀+(T_surface−T₀)erfc(x/2√(αt)). I’ll send you the template if you need it.

Here’s the link to the spreadsheet; it runs a 1‑inch steak at 550 °F, shows temp vs. depth over time. Just open it, check the heat flux, and tweak the grill temp to avoid that rock‑hard outcome you warned about. Happy cooking!