Preheat the oven to 375 °F (190 °C).
Oil a small saucepan that can go in the oven with coconut butter.
Cook the chopped turkey in a small skillet over medium heat. Add zucchini and onions, and continue cooking until vegetables are tender and turkey is cooked through.
Remove from heat and pour into the pan.
In a bowl, whisk the egg, the mustard and salt and pepper until a smooth mixture is obtained.
Add the grated cheese to the egg mixture and stir.
Pour this mixture over the turkey in the pan.
Place the pan in the preheated oven and bake for 20 minutes or until the cheese is melted and lightly browned on top.
Remove from the oven and serve immediately.