HEAT oil in a non-stick frying pan over medium-high heat. Add the onion and saute; remove.
Add spinach and cook until just wilted. Squeeze out excess moisture with paper towel. Roughly chop then combine with onion and Philly
PLACE bacon and tomatoes on a lined baking tray. Bake at 180°C for 10 minutes. Keep warm
BEAT the egg whites to soft peaks. Fold in the yolks and seasoning. Heat half the butter and extra oil in a 26cm non-stick frying pan over medium heat.
Add half the egg mixture and cook 3-4 minutes, or until almost cooked through.
Place under a hot grill for 2-3 minutes until set, then top half the omelette with half the Philly mixture and fold into a half circle. Repeat with remaining egg and Philly mixture
Serve half an omelette with some crispy bacon and cooked tomatoes