In a medium skillet over medium heat, sauté cubed plantain in coconut oil until browned on the exterior, about 10 minutes. Remove plantains from pan and set aside.
While plantains are sautéing, scramble eggs in a small bowl with a splash of milk. Add a sprinkle of freshly ground black pepper.
Start making omelettes, dividing ingredients in 1/3 to make 1 omelette at a time. Saute onions until translucent, then add bell peppers to cook. Finally, add spinach to quickly wilt.
Add plantains back to the pan and then add eggs.
Let cook until eggs are cooked through and carefully flip. Omelette should be crispy on the exterior. About 5-7 minutes total.
Repeat until all vegetables and eggs are used. You should be able to make 3 omelettes.