Adapted from a favorite recipe for baked steel cut oatmeal on my blog , which was originally adapted from Heidi Swanson's widely adored recipe, which I learned about via Molly Wizenberg's blog, Orangette.net.
Notes: You can prepare the whole dish the night before baking and bake in the morning. This eliminates work in the morning, but does not cut back on cooking time. Keep in mind this bakes for about 55 minutes.
If you are not avoiding dairy, cow's milk can be used in place of the almond milk. Other nut milks as well as coconut milk and soy milk can be used in place of the almond milk.
Original recipe also calls for cinnamon and melted butter, but I've been leaving them out. Use if you wish.
Vessels: When making individual portions, I use four 1/2-litre (about 2 cups) Weck jars, but pint-sized Ball jars or something similar would work well, too.
Preheat the oven to 375°F with a rack in the middle or top third of the oven. In a small bowl, mix together the oats, the nuts, baking powder, salt, and cinnamon, if using. If you are making individual portions, measure out a heaping 1/4 cup of the oat mix and transfer to each of 4 baking vessels (see notes above). Divide the remaining mix among the vessels. If you are making a single, large batch, transfer the mix to an 8- or 9-inch square or circular baking vessel. If you are using any fruit, add it to the baking vessel.
In a medium bowl, whisk together the milk, maple syrup, egg, vanilla, and melted butter, if using. If you are making individual portions, pour 1/2 cup plus 1 tablespoon of the liquid into each vessel and stir to combine. If you are making a single, large batch, pour the liquid mix over the dry ingredients and stir to combine.
Transfer pans or pan to the oven, and bake for 55 to 60 minutes or until the top is golden and the oat mixture has set. (Note: Check after 30 minutes, and if it looks as though it is browning quickly, turn oven down to 350ºF.) Remove from the oven, and allow to cool for a few minutes before serving.