Cardamom Baked French Toast

Name: Cardamom Baked French Toast
Ingredients: 4 cups whole milk; 1 teaspoon black peppercorns; 4 large eggs; 3 large egg yolks; 1/2 teaspoon kosher salt; 1/2 cup, plus 2 tablespoons granulated sugar, divided; 3/4 teaspoon ground cardamom, divided; 1/2 cup (1 stick) unsalted butter, softened, plus more for greasing; 1 (16-ounce) challah or brioche bread loaf, cut into 1-inch-thick slices; 2 tablespoons melted unsalted butter; 1 1/2 tablespoons Swedish pearl sugar or sanding sugar; Pure maple syrup, for serving