What you’ll need:
Grease 10 (8-ounce) ramekins with 1 tablespoon of the softened butter and arrange on a rimmed baking sheet.
Bring 2 quarts of water to boil over high heat. Add 1 1/2 teaspoons of the salt. Add the pumpkin and sweet potatoes and boil until soft, 25 to 30 minutes. Drain and transfer to a large bowl.
In a small saucepan, combine the ginger, cinnamon stick, star anise, and cloves with 1/4 cup water. Bring to boil over medium-high heat and boil for 5 minutes. Strain the water into a bowl and set aside.
Preheat the oven to 400 degrees F.
Using an electric mixer, blend the pumpkin, sweet potatoes, and the remaining 3 tablespoons butter on medium speed until smooth, about 3 minutes. Add the eggs, coconut milk, brown sugar, the remaining 3/4 teaspoon salt, the flour, and the reserved spice water and blend for 1 more minute or until smooth.
Pour the mixture into the prepared ramekins and bake for 30 to 40 minutes, until the custard is no longer wiggly and the tops are golden brown.
Remove from the oven and place on a wire rack to cool fully. Cover the ramekins with plastic wrap and chill in the refrigerator. Top with whipped cream, toasted coconut, and/or dark chocolate shavings if you like.