Prepare ingredients and equipment: measure oats and almond milk, slice the banana into thin rounds and set half aside for topping (reserving some banana keeps a fresh texture on top). Chop walnuts if not already chopped. Use a medium heavy-bottomed saucepan to prevent hot spots that can scorch the oats.

Toast the walnuts (high impact for flavor): heat a small dry skillet over medium heat, add the walnuts and toast, stirring, for 2–3 minutes until fragrant and lightly browned. Toasting releases the oils in the nuts and intensifies their flavor and crunch. Transfer to a bowl to stop cooking so they don’t burn.

Warm the almond milk: pour the almond milk into the saucepan and warm over medium heat until it just reaches a gentle simmer (small bubbles forming at the edges). Warming the liquid before adding oats shortens cook time and helps create a creamier texture because the oats start hydrating immediately and evenly.

Add oats and salt: stir in the rolled oats and the pinch of salt, then reduce heat to medium–low. Bring the mixture to a gentle simmer — not a rolling boil — because a vigorous boil will make the oats gummy and can scorch the bottom.

Cook, stirring frequently: cook the oats for 6–8 minutes, stirring or scraping the bottom and sides every 30–60 seconds. Stirring encourages the oats to release starch, which creates the creamy emulsion that makes stovetop oats luxurious. If the mixture thickens too fast, lower the heat and add 1–2 tablespoons of extra almond milk to loosen it.

Add banana to cook (for silkiness): when the oats are about 2 minutes from your desired thickness, stir in half the banana (mashed slightly with a fork). Cooking some banana into the oats naturally sweetens and enriches the porridge while adding body; saving some banana for topping keeps fresh texture contrast.

Finish with almond butter and cinnamon: remove the pot from the heat and stir in the almond butter and ground cinnamon (and vanilla if using). Adding the almond butter off the heat prevents overheating and preserves the nutty aroma; stirring it in emulsifies it into the oats for a satiny finish.

Sweeten to taste: taste the oats and add maple syrup if you want more sweetness. A tablespoon is a guideline — if your banana is very ripe you may need less. Add a tiny pinch of salt if flavors feel flat; salt brightens the sweetness and deepens the nutty notes.

Plate and garnish: divide the oatmeal between two bowls and top with the reserved banana slices and the toasted walnuts. For extra texture and presentation, swirl an extra 1/2 teaspoon of almond butter on each bowl and a light dusting of cinnamon.

Serve immediately: stovetop oatmeal is best fresh while warm and creamy. If you must hold it for a few minutes, keep the pot over the lowest possible heat and stir occasionally; add a splash of almond milk before serving to refresh the texture.