Cinnamon Baked French Toast

Name: Cinnamon Baked French Toast
Ingredients: Butter, for greasing; 1 loaf crusty sourdough or French bread; 8 whole eggs; 2 cups whole milk; 1/2 cup whipping (heavy) cream; 1/2 cup granulated sugar; 1/2 cup brown sugar; 2 tablespoons vanilla extract; 1/2 cup all-purpose flour; 1/2 cup firmly packed brown sugar; 1 teaspoon ground cinnamon; 1/4 teaspoon salt; Freshly grated nutmeg; 1 stick cold butter, cut into pieces, plus more for serving; Warm pancake syrup, for serving; 1 cup fresh blueberries, for serving