Slice the tops off of each head of garlic, exposing each clove. Drizzle with olive oil and season with salt and pepper. Wrap in aluminum foil and roast for an hour or until garlic is tender. Let garlic cool, then squeeze out each clove from the head.
In a large dutch oven, melt the butter over medium-high heat. Stir in the flour and cook until slightly nutty in aroma. Add in the roasted garlic and cook until a dark roux forms, about 5 minutes, stirring constantly. Whisk in the chicken stock until fully combined. Stir in 2 cups of water.
Add italian seasoning and salt and pepper to taste. Bring to a simmer and cook for 15 minutes.
Make the crostini. Preheat the oven to 400 degrees. Brush the bread with olive oil on both sides of the baguette and place on a baking sheet. Top with italian seasoning and cheese, then bake for 10 minutes until crisp and cheese has melted.
Stir in the cream to the soup and cook for 10 minutes at a low simmer. Serve with crostini and enjoy!