This aspiration is fairly straightforward for the most part. To unlock it, your sims need to eat 3 servings in a row, so they'll have to eat when they aren't hungry. It doesn't unlock if you space them out too far.
The final tier is the only fussy one, otherwise. Cook an excellent grilled cheese only seems to credit for single servings in my tests(group servings don't count for this tier, not sure if that's by design or if its a glitch). To eat a grilled cheese in space, you need to put the serving in your sims inventory. The option will be available when you first interact with the rocket.
Unfortunately, unless Grim is already in the social panel some poor Sim will have to make the ultimate sacrifice in order to complete this.
Summon grilled cheese instantly creates a single serving of good quality (might be random but was always good in my tests). Paint grilled cheese is pretty useless tbh, but the aspiration is tongue-in cheek so I didn't expect amazing results. I didn't test to see if higher painting skill unlocks better paintings. The aspiration does give comparable satisfaction to the others, so worth doing just for the points (albeit the missing tier reduces the over all total).
I'm tired and too lazy to proofread atm. Sorry for any incoherence and/or crimes against grammar. I just wanted to give some unofficial tips about my experience with the aspiration. I hope it is useful to some of you.