This can be done in software or hardware in either amplitude peaking with a rectifier measurement circuit or a phase as resonance using the MC4046 phase detector.
This freq. will lower with a various pots on stove top due to permeability but also lower in Q due to power loading.
If I were doing it, I might consider other methods.
Similar to Solar tracking which has a low Q Peak Power tracking point, a loaded induction coil will have low Q.
So if you wish maximum power, depending on freq and if high f; alum. or iron pot the loaded Q may not affect power significantly or not.
Solar tracking max power regulators use two MPPT methods worth considering perturbation and observation, (P&O) and InCon or Incremental Conductance
Solar uses DC , in this case AC so measuring phase current relative to voltage resolves optimum frequency, but you need to monitor load power in case of no load to shut off or monitor self heating or OTP or OCP from a no load situation.
So I would sweep f and measure power for peak and no load protection in addition to power modulation with power sensing. (V*I ) if you wanted to regulate power with dial regardless of load.