Peel the sweet potatoes, slice them, and steam until tender.

Once cooked, mash the sweet potatoes. Add the oatmeal and flour, and mix until you have a smooth dough. Divide the dough into 7 portions, roll each into a ball, and press to make a well in the center. Line a baking tray with parchment paper and place each dough ball on it. Bake at 200°F (about 93°C) for 7 minutes, until the crust firms up.

While baking, beat the eggs, then add the milk and mix well. After 7 minutes, remove the tray and pour the egg mixture into the wells of each sweet potato crust. Return to the oven and bake for about 30 minutes, until the egg filling is set and golden on top.

Let the cakes cool before placing them in paper liners.