Lightly butter 9 x 13-inch baking dish and set it aside. Add the cut sweet potatoes to a large stockpot and cover them with 6-inches of water.
Bring the water up to a boil over medium-high heat and cook the potatoes until they're fork-tender, or 30-35 minutes. Once they are soft, drain the sweet potatoes using a colander. Turn your oven on to 350°F (177°C).
Return the hot sweet potatoes back to the empty pot. Add the first quantity of unsalted butter to the pot and use a potato masher to mash the sweet potatoes and butter together until the potatoes are slightly chunky. Scrape the sides of the pot down with a rubber spatula to ensure the potatoes are free of lumps.
Next, add the coconut milk, brown sugar, pumpkin spice blend, salt, and vanilla extract to the pot. Use the masher to continue mashing and stirring the ingredients into the potatoes while you do so.
Once the coconut milk is fully mixed in, add the beaten eggs to the pot. Use a rubber spatula or spoon to mix these into the sweet potato mixture well.
Prepare the Coconut Pecan Topping
Add the coconut flakes, pecans, almond flour, brown sugar, unsalted butter, and pumpkin spice blend to a medium-size mixing bowl. Use your fingers or a fork to mash and mix everything together until the mixture clumps when squeezed in your hand.
Assemble, then Bake the Sweet Potato Casserole
Once the coconut pecan topping is mixed, scrape the mashed sweet potato mixture into the greased baking dish. Use a rubber spatula to smooth the sweet potatoes into an even layer in the baking dish.
Sprinkle the coconut pecan topping over the sweet potato layer, ensuring the topping is evenly distributed in an even layer. Put the baking dish into the preheated oven and bake the casserole for 35-40 minutes.
When baked, the top will be a dark, golden brown color, and the edges of the casserole will be slightly crusty. Remove the casserole from the oven and allow it to cool for 10-15 minutes before serving.
Notes
Swaps and Substitutions:
You can replace the full-fat coconut milk with lite if you need to, but the casserole won't taste as rich.
To replace the sweet potatoes with sweet potato puree, you'll need about 6 cups (1 1/2 kilos) for this recipe.
You can omit the eggs if you don't eat them or are allergic.
If you don't have coconut milk or are allergic, you can replace it with evaporated cow or soy milk.
Replace the coconut with more pecans.
If you don't like pecans, replace them with walnuts, cashews, or pistachios.
You can omit the almond flour or replace it with all-purpose flour or old-fashioned rolled oats.
If you have a nut allergy (but are okay with coconuts), replace the pecans with old-fashioned rolled oats.
Replace both the coconut and pecans with old-fashioned rolled oats.
Tips and Techniques:
If you don't want to mash too long, you can also melt the unsalted butter and the coconut pecan topping will mix quicker.
Make-Ahead Suggestions:
You can boil the sweet potatoes a day or two ahead and mash them without the butter. Mash and store them in the fridge until you're ready to make the recipe.
Keep the mashed sweet potatoes and the coconut pecan topping separate and assemble the recipe right before you plan to bake it.
You can store both components separately in covered containers in the fridge for up to 2 days.
Storage Instructions:
Store leftover sweet potato casserole in a covered container in the fridge for up to 3 days.
Reheat the portion you plan to eat into the microwave on high for 1 1/2 minutes (or until warmed through).
Freezer Instructions:
To freeze Baked Sweet Potato Casserole:
Cool the casserole completely.
Wrap the dish well in plastic wrap or foil and freeze the casserole for up to 4 months.
Thaw it under refrigeration and reheat as instructed above.
After thawing, put the covered (in foil) dish into the oven and reheat for 20 minutes on 200°F (93°C) until warm in the center.