That is a very good question.
Not sure how big the oven is but if it fits in your luggage, you can absolutely bring one back. You may need to report it to the custom for its value. As long as it is for personal use they should leave you alone.
Technical pizza making equipment is duty free.
If someone sends it to you, make sure it is extrimly well packed as the various shipping company are extrimly rough and careless. Unfortunately I know too much about that. In that case make sure it is listed as a present for the custom or you need a license to bring that here.
Check the oven can take 50 and 60 hertz as it is not the same in EU and US and will fry any electrical equipment.
Good luck with all that