Place an overlapping layer of sweet potato slices on the bottom of the dish; alternate with sliced shallots. Continue until all sweet potato and shallot slices are used up: this should make 4 layers of sweet potato & 3 of shallots in a 7 x 11 dish. Save the larger slices for the final layer.
Preheat oven to 400F while you make the sauce.
Add the coconut butter to a saucepan over very low heat; when melted, add the almond flour.
Whisk almond flour into coconut butter until large crumbs are formed.
Add coconut milk in half cup increments, whisking each time to combine. There will be a few lumps which is fine!