As summer shuffles on, between the sounds of waves crashing at the beach, the sizzling of grills, and the evening chirping of birds and frogs comes the quiet yet insistent wail of the home gardener.

Cooking oatmeal on the stovetop according to the label directions is the best method: It’s quick and easy, isn’t prone to boiling over, and yields a delightful tender-chewy texture. The Instant Pot ...