Cuisinart toaster oven function knob broke

The "function" knob (broil, toast, bake) on my Cuisinart toaster oven broke off while I was toasting so it's stuck on "toast".

There is a D-shaped thingy plastic half inch long sticking out from inside where the broken knob used to be attached.

If I grasp it with a longnosed plier, I can turn it but I'm afraid if I keep doing that, it may get misshapen and be useless later.

How can I replace the knob?