Where does “tosten” come from?

tosten (Middle English) comes from Old French toster, from Latin tostus, from Proto-Italic *torstos.

tosten (Middle English): To toast; to brown bread; To burn or heat

Definitions

Step	Language	Word	Meaning
1	Old French	toster	to roast, grill
2	Latin	tostus	roasted, toasted, scorched, having been roasted;...
3	Proto-Italic	*torstos	—

tosten — Etymology, Origin & Word History | Etymology Explorer