Step 1 Set a small non-stick ovenproof frying pan over medium heat and spray with olive oil. Add onion and chilli to pan; cook for 2–3 minutes, or until soft. Set aside.
Step 2 Spray frying pan with oil again. Add potato to pan, in batches, and cook for 3–4 minutes per side, or until slices are just soft.
Step 3 Spray frying pan with oil again. Arrange half of the potato, slightly overlapping slices, in base of pan. Top potato slices with half of the onion–chilli mixture; spoon baked beans over mixture. Top baked beans with remaining potato; top potato with remaining onion–chilli mixture. Arrange half of the cherry tomatoes on top of mixture.
Step 4 Whisk eggs with 1/4 cup water in a large bowl; season with black pepper. Pour egg mixture into pan and reduce heat to low. As omelette sets, gently lift edge to let any raw egg run underneath; repeat 2–3 times. Cook for 10–15 minutes, or until almost set.
Step 5 Scatter omelette with chopped parsley and serve immediately.