The answer to that is…‘maybe’! It depends on if you damaged the MCU when you toasted the MosFET. You can try it, just remove the blown mosfet being careful to not pull up the circuit board pad - use a soldering iron. You can use any ground but GND is available on the ‘source’ pin which is the pad under the gate
alternatively.
The larger MosFET that is currently assigned to Extruder 2 is a STP55nf06L
The pin arrangement is as follows -
so the gate signal can be found here -
Again, you can remove the MosFET and solder to the gate (PWM) and source (pin 3) (GND) pins …however, configuring the firmware to allow the use of that mosfet for laser pwm out is another question…