Both FLs are talented but poor palace chefs, the MLs are crown princes or emperors, and the two slowly fall in love despite their differences. Both dramas have a palace setting.
Both have the ML and FL who lead very different lives accidentally body swapping due to some natural event (eclipse vs. lightning) and undergoing character growth as a result of the swap.
Both dramas have these funny skits at the end/begging of each episode. Delightful girl Choon Hyang has historical skits while the main story is set in modern time and King is not easy has modern skits while having a historical setting for the main story.
Both dramas are set in the palace in historical times, with an emperor ML and a FL who is very talented in cooking. Both are lighter, enjoyable dramas.
They are very similar productions. Both Royal harem comedies, of high quality (sadly too few eps) where the female lead does NOT have a high pitched voice or a completely vapid personality.