Spread the bread on a rimmed baking sheet and let the slices dry out for 4-6 hours.
Preheat the oven to 375 degrees F.
Line a quarter sheet pan with parchment paper (12 1/2x9 1/2-inch).
Toss the tomatoes with 1 tablespoon of the olive oil and season them to taste with the salt and the pepper.
Spread the tomatoes on one side of the prepared pan.
On the other side of the pan, arrange the bacon in a single layer.
Roast until the tomatoes are wrinkled and begin to soften and the bacon is about three-quarters of the way cooked, about 20-25 minutes.
Transfer the pan from the oven and add the tomatoes and the bacon to a plate.
Discard the fat from the pan and remove the parchment paper.
Wash the sheet and then brush it with the extra olive oil.
In a bowl, whisk together the eggs, the milk, 1 teaspoon of the salt, and 1/2 teaspoon of the pepper.
Dip the bread slices, one at a time, into the egg mixture, turning to coat.
Arrange the soaked slices of bread on the prepared sheet in shingled, overlapping layers.
Pour the remaining egg mixture evenly over the pieces of bread and top them with the parsley and the cheese.
Top the shingled bread with the bacon and the tomatoes.
Refrigerate the French toast, covered, for at least 1 hour and up to 24 hours.
Preheat the oven to 375 degrees F.
Place the sheet pan over a larger baking sheet to prevent it from boiling over.
Bake the French toast, uncovered, for 15 minutes.
Reduce the temperature to 350 degrees F and continue to bake until puffed and cooked through, about 20-25 minutes.
Let cool slightly before serving.