PAK CHOI, SWEET POTATO AND CHORIZO FRITTATA RECIPE

300g sweet potatoes (unpeeled), cut into 2cm pieces • 6 tbsp extra virgin olive oil • 235g pack pak choi, trimmed and halved lengthways • 1 red onion, thinly sliced • 150g baby plum tomatoes • 120g cooking chorizo, thinly sliced • 12 eggs • ½ x 25g pack flat leaf parsley, leaves finely chopped • 1 garlic clove, crushed