Pre heat your oven to 200 degrees Celsius and line a baking tray with paper.
Chop the potatoes into 2cm cubes and coat in the olive oil, salt and pepper. Roast for 20-30 minutes or until golden brown.
Heat the olive oil in a pan over a medium low heat and add in the onion and a pinch of salt, cook this down slowly for 10-15 minutes or until the onions are nice and soft.
While the onions cook whisk up the eggs in a large bowl with the milk, herbs, parmesan and a generous pinch of salt and pepper.
Once the onions are soft and caramelised add in the garlic and balsamic vinegar, stir to coat. Add in the chopped kale and cook for a few minutes until wilted.
Line a tray or oven safe skillet with some baking paper, add in the roasted potatoes and the onion and kale mixture then pour over the egg mixture.
Bake for 25-30 minutes or until golden brown and cooked through. Serve with a fresh green salad.