Add whole potatoes to a steamer over boiling water.
Steam for about 15 minutes or until just tender. Be sure to check the potato with a skewer to ensure it is tender and not still firm. Steam longer if the potatoes are still firm.
Remove potatoes from steamer and allow to cool then thickly slice.
Pre-heat a fan forced oven to 180°C (350°F).
Add olive oil to a small (approx 25cm) oven proof frying pan over medium high heat.
Add chorizo and cook for a few minutes until golden. Remove from pan and set aside in a medium bowl.
Add onion, capsicum and garlic to pan and cook for about 5 minutes or so.
Add cherry tomato and cook a further 2 minutes.
Remove pan from heat and transfer all contents from pan to the bowl with the chorizo.
In a separate large bowl, add eggs and whisk.
Add cheese, parsley & lemon zest. Stir to mix through.
Add sliced potato & chorizo mixture to the bowl and stir to mix through and coat with egg.
Pour the combined mixture back into the frying pan and evenly spread the contents.
Place in oven and bake for 20 minutes or so until set and browned.
Remove from oven, loosen the edge with a spatula and let set for a few minutes.