You'll have to get a 12 volt inverter with enough wattage to power a toaster. You'll pop the panel off that covers the battery. Use jumper cables to connect the battery to the inverter. Plug your toaster into the inverter.
Your car must be on. A toaster would wreck that battery fast without the car charging it at the same time.
You can't use a 12v socket to power the inverter. A toaster would blow the fuse.
sure. toaster, microwave, inductive cooktop..... just not all at the same time.
you can extract up to 1500 watts or so from your 12v connection points and run a 1500watt inverter.