Preheat oven to 350F.
Heat 1 teaspoon oil in small pan over high heat. Add onion and bacon and sauté until bacon is crisp – about 2 minutes. Remove from heat and set aside in pan.
Cut bread into circles using a cookie cutter or glass. Use a rolling pin to flatten the bread. Lightly spray 6 muffin tin holes with cooking spray, then press the bread into the muffin tin.
Place in the oven for 3 minutes, or until bread is slightly dried but not browned. Remove from oven and set aside.
Whisk together the egg, milk, parsley and a pinch of salt and pepper.
Divide the bacon mixture between the 6 toast cups, then the cheese.
Pour 2½ tablespoons of egg mixture into each cup, then place in the oven. Bake for 12 to 15 minutes until the top is lightly golden and the filling is set.
Remove from oven and rest for 5 minutes before serving. Garnish with extra parsley, and serve warm.