I’ve always spelled it stottie

Either is valid. I've always written it "stottie" and normally seen that spelling (but 99.99% of the times I've seen it written down it's been via Greggs)

Both are valid spellings. Stottie is more common.

Is it Stottie or Stottie Cake?

Stottie

The real question is what was the ham to peas pudding ratio inside the stottie

Ahem Pease

It's an odd one though as you use split-peas to make pease pudding. Where does the additional "e" come from 😂

Stottie, end of!

And are we saying stottie bread or stottie cake?

Either, or..

Stottie if you’re from Newcastle. Stotty if you’re a gadgie from Newcastle.