焼く言うのは「熱を加えて食べ物を作る」... What you can add is ・という意味です。 or ・ことです。 I hope I answer the question.

「焼く」と言うのは「熱を加えて食べ物を作る」／"です" comes just after a noun, but "〇〇〇を作る" is not a noun. So, you can't use "です" or "のです" here.／If you attach "こと" at the end of "〇〇〇を作る", it makes a noun. So, "〇〇〇を作ることです" works here. It means "焼く" is to cook food by heating it.／If you attach "という意味" at the end of "〇〇〇を作る", it also makes a noun. So, "〇〇〇を作るという意味です" works here too. It is translated as "焼く" means "cook food by heating it".

Yoo! I'm still here! lol