Preheat the oven to 400 degrees.
Lay out the sliced sweet potatoes in a pie dish in a crust-like fashion. Brush some olive oil onto the sweet potato slices with a basting brush. Bake the sweet potato crust for 20 minutes.
Once the 20 minutes is up, let the sweet potato crust cool for 5 minutes. Reduce the oven heat to 375 degrees.
Top the sweet potato crust with a layer of mustard. Evenly distribute 3 Tbs of mustard to the sweet potato crust and spread it around with a rubber spatula. (It doesn't have to be perfect).
Put the tuna into a bowl and mash it with a fork until it crumbles. Then, sprinkle the tuna on top of the layer of mustard.
In a medium bowl, mix the eggs, coconut milk or cream, salt, pepper, and basil together in a bowl with a whisk. Add the cherry tomatoes and mix.
Pour the egg mixture on top of the tuna.
Put the whole thing into the oven for 40 minutes. Let the quiche sit for 5-10 minutes. Slice and Enjoy!