Soup or stew is about the only traditional way to prepare lentils pretty much everywhere, traditionally eaten with bread. The lentil+wheat/rye combo is to Indo-European cooking what beans+maize is to American cooking, and rice+beans to Asia. Africa is also lentil territory the grain situation there is... complex.

In any case yes it's going to be soup or stew in whatever viscosity and degree of mushiness you want but you'll find a metric fuckton of different recipes.

If you want something ready-made there's lentil crisps which actually are very good but also quite a bit more expensive than the usual potato or maize fare.

So, you caveat your statement with ready-made foods, but that's kinda disingenuous, as you're vegan. That means you have to seek out your food in general, and it's more likely that your food may contain lentils, like bean patties that replace beef patties for burgers. Maybe not all of them, but they definitely exist. I imagine a lot of pre-made vegan meals also probably intentionally make up for difficiencies natural to the diet.

I like to cook my own food, so everything I make could be counted as "seeking out". Split peas, lentils, and dal are common beans I keep, along with northern beans, black beans, kidney beans, pinto beans, and pigeon peas.

When I ate pasta more, I also often bought lentil based pasta for a quick meal, so if you're making anything it isn't too hard. Also made lentils and rice often. My bean/pasta drawer(obvious none of the canned stuff):

https://i.imgur.com/ATSvuGy.jpeg

Accidentally hit post before finishing this.