DIY Induction Heater failure - MOSFET overheat
Does your circuit oscillate? If not, then both mosfets conduct at the same time and the behaviour is like you presented. Both mosfets dissipate all which is available. 

One error which prevents the oscillation or lower its frequency to uselessly low is to use some random parts instead of the proper ones. For example 1N4007 instead of ultra fast UF4007. Another error is to have no supply voltage decoupling and about 20 times too long wiring. Your wiring is a bigger coil than the heating coil.

Make your circuit as compact as the model, use exactly right parts and have some big capacitor between Vcc and GND as near the circuit as possible. Be also sure that theres no connection between the turns of L1, if it's not insulated. Any connection is a short circuit.

Without having an oscilloscope debugging is very difficult because a multimeter shows virtually nothing about oscillations.