In a large skillet, melt 2 tablespoons of butter with 1 tablespoon of olive oil over medium-low heat. Add sliced medium onions and cook slowly for about 20-30 minutes, stirring often, until they are golden brown and tender. This step infuses the Savoury Baked French Toast with rich depth. Once done, transfer the caramelized onions to a bowl and set aside.

Using the same skillet, increase the heat to medium and add 6 ounces of diced bacon. Cook for about 8-10 minutes or until the bacon is crispy, stirring occasionally to ensure it browns evenly. Once cooked, drain any excess fat on paper towels, and then set the crispy bacon aside, allowing it to cool slightly before combining with other ingredients.

In a large mixing bowl, crack open 6 large eggs and whisk them together with 2 cups of whole milk, 1 teaspoon salt, ½ teaspoon black pepper, and optional 1 teaspoon of mustard powder. Whisk vigorously for about 1-2 minutes until the mixture is well combined and slightly frothy.

In a large bowl, mix together 1 loaf of stale baguette or French bread cut into cubes, the caramelized onions, cooked bacon, and half of your chosen grated cheese (about 1 cup). Pour the prepared egg mixture over the bread mixture and gently fold everything together until well combined. Allow the mixture to sit for 30 minutes.

Preheat your oven to 350°F (177°C). Transfer your combined Savoury Baked French Toast mixture into a greased baking dish. Sprinkle the remaining cheese evenly over the top. Bake for 50-60 minutes or until the edges are set and the top is golden brown.

After baking, let the Savoury Baked French Toast cool in the dish for about 5-10 minutes to allow it to set. Slice into squares and garnish with freshly chopped parsley.