Whether you're from Italy and call your grits polenta or you're from the South and call your polenta grits, you're talking about stone-ground cornmeal that cooks by absorbing water, like rice does in a rice cooker. In fact, you can cook any grain that absorbs water in a rice cooker using the same liquid-to-grain ratio, grits and polenta included. Grits require stirring when cooked uncovered, but not in a rice cooker. When cooked in a rice cooker, moisture condenses on the bottom of the lid and drips back onto the grits, which keeps them fluid.
Add 1 part grits and 4 parts cold water or stock to the rice cooker. Season the water or stock to taste with kosher salt and cover.
Set the rice cooker to the standard or White Rice setting. Come back in about 20 minutes or when the rice cooker switches to Warm mode.
Uncover the rice cooker and transfer the grits to a mixing bowl. Stir the grits several times and taste them.
Adjust the seasoning with kosher salt, freshly ground black pepper and butter, if desired. If you are adding freshly chopped herbs, add them while hot.