1Preheat your oven to 180°C (350°F).
Chop the onion and cabbage finely.
In a large oven-safe skillet, melt the butter over medium heat.
Add the chopped onion and sauté until translucent, about 5 minutes.
Add the cabbage to the skillet and cook until softened, about 5-7 minutes.
Dice the ham and add it to the skillet, stirring to combine.
In a bowl, beat the eggs with salt and black pepper.
Pour the egg mixture over the ham and cabbage in the skillet.
Cook on the stovetop for about 5 minutes, until the edges start to set.
Transfer the skillet to the preheated oven and bake for 15-20 minutes, or until the frittata is fully set and lightly golden on top.
Remove from the oven and let it cool slightly before slicing and serving.