Preheat your oven to 350°F (175°C).

Grease a 9x13-inch baking dish with a little coconut oil or line it with parchment for easy serving.

Peel and cube the sweet potatoes into roughly 1–1½ inch pieces so they cook evenly.

Fill a large pot with cold water, salt it lightly, and bring it to a boil while you finish prepping.

Add the sweet potato cubes to the boiling water and return to a gentle boil.

Cook until the potatoes are very fork-tender — about 12–20 minutes depending on size. A knife should slide through with no resistance.

Drain well in a colander and return the drained potatoes to the empty warm pot for a minute so excess steam escapes.

Pro tip: Letting the potatoes sit in the warm, drained pot for a minute or two helps evaporate extra water so your mash won’t be watery.

Mash the potatoes using a potato masher for a rustic texture or a hand mixer for very smooth results.

Add the canned coconut milk, maple syrup, melted coconut oil (or vegan butter), vanilla extract, cinnamon, nutmeg, and a pinch of salt.

Mix until the filling is silky and spreadable — not soupy. Taste and adjust: add a touch more salt if it needs contrast, or a splash more maple syrup if you like it sweeter.

Spoon or spread the mashed mixture evenly into your prepared baking dish.

Pro tip: If using a hand mixer, start on low so the mash doesn’t splash; increase speed only after the potatoes start to break down.

Warm a small skillet over medium heat and lightly toast the chopped pecans for 2–4 minutes, stirring, until they smell toasty — this deepens their flavor. Transfer to a bowl to cool.

In a bowl, combine the rolled oats, toasted pecans, almond flour, coconut sugar, and cinnamon.

Pour in the melted coconut oil and stir until the mixture clumps together into a coarse crumble. It should hold together when pressed.

Taste a tiny bit (it’s okay — you earned it) and adjust sweetness if you want a more pronounced contrast to the sweet potato base.

Pro tip: Toasting the nuts is one of the easiest flavor upgrades — don’t skip it.

Evenly sprinkle the oat-pecan topping over the sweet potato layer. Press lightly so it adheres but keep the crumbly texture.

If you like an extra-nutty finish, scatter a few whole pecan halves on top for presentation.

For a sweeter, classic finish, you can dot with a handful of dairy-free mini marshmallows in the last 5 minutes of baking (optional).

Place the casserole in the preheated oven and bake for 25–30 minutes, until the topping is golden and the edges are bubbling.

If you want a crispier top, switch the oven to broil for 1–2 minutes — watch closely so it doesn’t burn.

Remove from the oven and let rest for 10 minutes before serving so the filling sets slightly and is easier to scoop.

Pro tip: If the topping starts to brown too quickly but the inside needs more time, tent the dish loosely with foil and finish baking.

Make-ahead (same day): Assemble the casserole, cover tightly with plastic wrap or foil, and refrigerate for up to 24 hours. Bake straight from the fridge — add 10–15 minutes to the bake time and check for bubbling edges. Let rest a bit before serving.

Make-ahead (freeze): Bake first, cool completely, then wrap tightly and freeze up to 2 months. Thaw in the fridge overnight before reheating.

Storing: Keep leftovers covered in the fridge for 3–4 days.

Reheating: Warm individual servings in the microwave for 60–90 seconds, or reheat the whole dish at 325°F (160°C) for 15–25 minutes (covered), uncovering for the last 5–10 minutes to crisp the topping.

Pro tip: If baking from chilled, let the dish sit at room temperature for 10–15 minutes while the oven heats — it helps the casserole warm through more evenly and reduces extra bake time.