I think the confusion is that in English we don't really have separate words for cooking-as-chore and cooking-as-art.

Lazy beans on toast or heating a frozen pizza is the first kind but not the second. There's no creative input, no method. You're just trying not to ruin your ingredients and end up with something edible. You're cooking but you're not cooking.

I'd say it's proper cooking if you're making decisions about what goes into it. Heating up beans and bread? Not cooking. Heating up beans and bread, adding some thyme and black pepper to the beans in the process? Cooking. Very simple cooking, but cooking all the same.

If I have to break out anything more than a plate/bowl and utensils then it's cooking.

Food Network, Tick Tock, and Youtube have turned everyone into gatekeeping snobs. Tell your friend that Carl Sagan said that it doesn't count as "made from scratch" unless the first step in the recipe is "create the universe".

Just reheating precooked food is just that, reheating.

it's all cooking

If all you have to do is heat something up, you are not cooking.

It counts as cooking when you start needing to prepare and combine ingredients.

Canned soup is not cooking.

Making a grilled cheese sandwich to go along with your canned soup would be cooking though, because it requires preparing bread, cheese, and butter (usually) and then combining then cooking the ingredients in a particular way.

Beans on toast is like crackers with soup.

Not cooking.

America's Test Kitchen said it was OK to use garlic powder or granulated garlic and people's heads exploded.

Unless they're fermenting their own soy sauce out back, or making their own jello/ gelatine (look it up) if say it's fair to call it cooking.

However, cooking, made from scratch and farm to table are all different.

You're not really making your own bread unless you grow and harvest the ingredients yourself. What do you mean you don't mill your own grains? Refine your own sugar?Can't really even call yourself a baker unless you build your own oven. /s

Cooking and baking are basically ALL prep work and cleanup. The actual cooking and baking is overall a pretty small fraction of the overall effort that goes into making dinner or a loaf of bread. Go ahead and feel proud of yourself if you take on more of those preparatory tasks, IF it makes for a better end result. But that doesn't mean you get to act superior to somebody else on a different path of their own personal cooking journey. Drawing an arbitrary line in the sand and saying "this is cooking, but that is not" is kind of like drawing a line between blue and indigo on a rainbow. It's arbitrary and adds little to good the discussion.

Go ahead and cheat on those components where it works. Not everybody has the time, space, energy, or skill to make every bread, sauce, or spice blend from scratch. If you can make something better by getting back to the basics and fundamental ingredients, go for it! But let's be honest when it's more about pride than the final product, enjoyment of the meal.

Personally, the biggest reason I prefer to avoid pre-prepared foods that only require heating is so that I can avoid certain common ingredients that are often pumped into those things in insane proportions, particularly salt and sugar. It's not so that I can feel proud of an arbitrary label.

Cooking is just the act of preparing food, especially by heating. Anything else is just people being snobs. Just go prepare your food and stop caring about peoples opinions on it.

Reheating is cooking. Not all cooking is reheating.

For me, I've always gone by the typical english definition of "combining and heating" ingredients.

If you've combined more than one item together and applied heat somehow, that counts as cooking, otherwise you're doing something else. Like, if I made myself a cold sandwich, I wouldn't say I 'cooked' a sandwich and the same for if I threw a burrito in the microwave.

So, from that, as long as you either warmed up the beans or threw the bread in the toaster and those items weren't pre-combined somehow, I'd personally say you cooked it.

Ask him to define cooking any way he likes => point out preparing toast falls into that definition => beans on toast is cooking QED