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Gourmet Cooking is a skill introduced with the base game of The Sims 4. It's functionally similar to Cooking and Baking but uses its own set of recipes. Gourmet Cooking can first be accessed when a Sim reaches Level 6 of the standard Cooking skill and attempts to make their first gourmet meal, which is usually garlic noodles.
Gourmet meals take roughly the same amount of time to cook and serve as standard meals, but they tend to be more filling and more easily apply positive moodlet buffs to the eaters. Generally gourmet meals are safe to cook too; by the time a Sim can make them, their standard Cooking skill is so high that it's unlikely they'll burn down the kitchen!
Note that gourmet meals, while more satisfying, are generally fattier than standard meals. Ergo your Sims who eat a lot of gourmet meals tend to be fatter than other Sims. If you don't care about your Sims' appearance this isn't a big deal, but it's something to keep in mind if you want your Sims to appear fit.
