Chocolate mousse would be very low on my list of essential recipes 😂 A basic cake recipe whilst not essential is a good skill to have and likely to be popular!
My experience of being a student is that the most popular meals are things like curry, chilli, pasta, pizza, noodles, fry ups etc.
I don’t think you need to teach specific dishes but rather skills. I think a basic tomato based sauce which can then be a base for bollognaise/ chilli/ lasagne etc is essential. So how to cook off the onions/ garlic etc, how to brown and cook mince etc, when you add different vegetables. Similarly how to make a curry - how to braise the meat, when you add chopped tomatoes/ coconut milk if using a curry paste etc.
Then how to cook pasta, rice, baked potatoes, boiled potatoes, noodles, how to cook basic veg - boiled, steamed or stir-fried. How to make a white or cheese sauce. How to roast, fry, grill etc meats (chicken, bacon, sausages etc). How to cook eggs (scrambled, fried, omelette etc).
Once you have a basic knowledge of how to cook things then it’s easy and fairly stress free to follow a recipe when you want to make a specific meal and far more useful than knowing how to cook a handful of meals but not really knowing how to transfer the skills.