Well, that's homemade, any further steps back on the scratch ladder and you're gardening, not cooking. It's obviously tricky to define, but it comes down to any case where you're forfeiting control of the final product in the name of speed or convenience. I'm not gonna render down pig skin and bone to make gelatin just so I can say my signature dark mint chocolate mousse is 'authentically homemade'. It's just a setting agent, it has no meaningful effect on flavor, texture, etc that I could really effect by going down to the butchers and getting a pork shank so I can make gelatin.

But where there is a difference between 'just heat' and 'from scratch' I think we have to say that whenever you remove a step that would give you meaningful control over the final product in favor of convenience that it removes a bit of the 'homemade'-ness, and soup being soup, for most soups there's not a lot of grey area to play with. Using a jiffy mix to make cookies is still homemade, because it's really just pre-mixing a fairly standard combination of dry ingredients, it has no meaningful effect on the final product compared to scratch, but even that's a pretty gray area. I mean I could say 'this salad is homemade' and just dump some lettuce in a bowl, but that clearly isn't what's meant for something so simple... 'this vinaigrette is homemade' would be a different story.

I would say, if you're using a recipe that would look straight out of the classic Betty Crocker Cookbook, then it's homemade, that's a good rule of thumb I think. And any case where a convenience is being added that doesn't stomp on control, then still homemade, pretty arbitrary yeah, but it has to be.