Measure the chia seeds and almond milk precisely: 4 tablespoons chia to 1 1/2 cups almond milk. This ratio (roughly 1:8 by weight/volume) yields a pudding that's set but still spoonable. If you add too many chia seeds it becomes overly gelatinous; too few and it will be loose.

Warm the almond milk briefly (optional): pour the 1 1/2 cups almond milk into a small saucepan and warm over low heat until just slightly warm to the touch (30–60 seconds). Warming helps the chia hydrate a touch faster and lets the maple and vanilla perfume the milk more readily. Do not boil—the goal is gentle warmth, not cooking.

Combine the base: in a medium mixing bowl whisk together the warm almond milk, 1 tablespoon maple syrup, 1/2 teaspoon vanilla extract (if using), a pinch of cinnamon and a pinch of fine sea salt. The salt brightens the sweetness and accentuates the other flavors; cinnamon is toasted aroma and depth.

Whisk in the chia seeds: add 4 tablespoons chia seeds and whisk vigorously for 20–30 seconds to distribute the seeds and break up clumps. Whisking at the start prevents the seeds from sinking and forming lumps. A tight whisk or fork works well.

Let the mixture rest for 5 minutes, then whisk again. Chia seeds swell quickly and can form a skin on top; stirring after a short rest ensures an even texture throughout. Alternatively, transfer to a jar, seal and give it a vigorous shake to mix.

Chill the pudding: cover the bowl (or jar) and refrigerate for at least 2 hours or overnight. Chilling gives the chia seeds time to fully hydrate and achieve that custard-like consistency. If you're short on time, a minimum of 30–45 minutes will thicken it somewhat but won’t reach the same silkiness.

Toast the walnuts while the pudding chills: place the 2 tablespoons chopped walnuts in a dry skillet over medium heat. Toast, stirring frequently, for 1–2 minutes until fragrant and slightly darker—watch closely so they don't burn. Toasting releases the walnuts’ oils and intensifies their flavor and crunch.

Prepare the banana: slice the medium banana into rounds. If you want extra banana flavor throughout, mash half the banana with the back of a fork and fold it into the chilled pudding before serving; reserve the other half for topping. Mashing adds natural sweetness and a silkier mouthfeel.

Assemble each serving: divide the chia pudding between two bowls or jars. If you folded mashed banana into the pudding, spoon the pudding evenly. Top each portion with sliced banana and the toasted walnuts. Finish with a tiny extra drizzle of maple syrup and a light dusting of cinnamon if you like for presentation and an extra pop of sweetness.

Serve and store: serve chilled. Leftovers will keep in an airtight container in the refrigerator for up to 4 days; the texture may continue to thicken—stir in a splash of almond milk before serving to loosen if needed.