Step 1

In a pot, add the sweet potatoes and enough of the cold water to just cover them.

Step 2

Place the pot over high heat and bring the water to a boil.

Step 3

Cook the sweet potatoes until they are fork-tender, about 20-30 minutes.

Step 4

Drain the sweet potatoes.

Step 5

In a small saucepan over medium heat, melt 2 tablespoons of the butter.

Step 6

Cook the melted butter, while whisking constantly, until little brown bits appear in the pan, about 4-5 minutes.

Step 7

Transfer the saucepan from the heat.

Step 8

Preheat the oven to 375 degrees F.

Step 9

In a large mixing bowl, add the sweet potatoes, the browned butter, 2 tablespoons of the brown sugar, the maple syrup, the coconut milk, the vanilla extract, 1/2 teaspoon of the cinnamon, 1/4 teaspoon of the nutmeg, and 1/4 teaspoon of the salt and using an electric handheld mixer, beat until combined, about 30 seconds.

Step 10

Increase the mixing speed to medium and beat the sweet potato mixture until whipped and fluffy, about 1-2 minutes.

Step 11

In a 9-inch round tart pan or a 9x13-inch casserole dish, add the sweet potato mixture and spread it out evenly.

Step 12

In a bowl, add the oats, the flour, the pecans, the flaked coconut, the remaining brown sugar, the remaining cinnamon, the extra nutmeg, and the extra salt and mix until thoroughly combined.

Step 13

Add the remaining softened butter to the oat mixture and using your clean hands or a fork, mix until the oat mixture is completely moistened and it clumps together into a crumble.

Step 14

Sprinkle the crumble mixture over the perimeter of the sweet potato mixture, leaving an empty space in the middle. If you are not using marshmallows, spread the crumble mixture evenly over the sweet potato mixture.

Step 15

Add the marshmallows to the empty middle space over the sweet potato mixture.

Step 16

Bake until the crumble topping is golden and the marshmallows are melty and slightly browned, about 20-25 minutes.

Step 17

Serve hot.