The good news is the game actually does offer a very wide variety of foods you can make.

RS Wiki Topic of the cooking Skill

As a few pointed out, there is 1 minigame centered on Cooking. Lots of Gnomish Foods and alcohol you can make

There is an entire thing of Brewing. It's somewhat limited in what you can make.

Wide variety of pizza, potatoes, stews, Ughtanki Kebabs, pies, and other stuff you can make. Even up to the Primal Feast. I should note that some ingredients aren't tradeable and can require using skills in Hunter, Fishing, or combat.

Several quests focus on cooking things you can actually make and eat yourself: Recipe for Disaster (which has multiple parts), Chef's Assistant (cheesecake versions) ... the list goes on.

Just note that for the recipes from quests ... you will have to train other skills, possibly including combat.

You can also make some foods in The Arc. Again, these can require a variety of skills to end up making them.

Sadly, the game does have a heavy focus on Fish being the primary means of player to eat/heal, as such, the player driven market only focuses on foods that heal a lot in a single bit or somehow provide a high skilling boost at least relative to what the maximum boost is).

So Hunter will only provide some very low level stuff, Farming tends to focus on the extreme ends for providing ingredients, and unless you intend to try to buy everything, you will likely need to take up Fishing.