Does smelling burnt toast (when there isn't any) a sign that I have a brain tumor?

No. Not necessarily. They can be indicators. But you would likely be having other symptoms as well, such as headaches (chronic), dizziness, nausea, vomiting, cognitive problems and more… see Mayo Clinic for details

There was a PSA series on historic Canadians that had a line in it (about 20 years ago) that suggested an Epileptic would smell burnt toast before the onset of her seizures. This particular vignette was on Dr. Wilder Penifield and Dr. Herbet Jasper and their pioneering research into neurology.

Thanks to those Canadian Heritage PSA’s, if anyone in Canada says they smell burnt toast, everyone always asks if they are about to have a seizure.

pixelnumber is probably completely correct. Even so, it’d be a really good idea to see a doctor about this if it happens with any kind of frequency.

I was smelling burnt toast everyday and I thought it was my skin
I was in Florida and walking for 2 to 3 hours a day in the heat..
But, none of this happened until about 3 months after I quit
smoking…I have further learned that I am Lactose and Fruitose
intolorant

all food smell burnt to me.If I open a coffee jar it takes me back.normal smells from cooking are absent.everything smells burnt.Am I nuts?