Adjust the oven rack to the lower third position and preheat the oven to 350°F (177°C). Spray a 9×9 inch square pan, or an 11×7 inch rectangle pan with nonstick spray. Any similar size pan that holds around 3 quarts works, though 8×8 inch square pan would be too small. The pictured dish I’m using is this white casserole dish. See recipe Note for 9×13 inch pan.

Whisk all of the ingredients together in 1 large bowl. Pour into prepared baking pan. Top with nuts, if desired. (Or stir into the oatmeal mixture.)

Bake for 35 minutes or until the center appears *almost* set, which gives us a soft oatmeal as pictured above. For drier and more solid baked oatmeal, bake until center has set.

Cool for 5 minutes before serving. Spoon or slice and serve with yogurt, if desired. Cover leftovers tightly and refrigerate for up to 1 week.