8 large slices challah or good-quality sandwich bread, sliced ½-inch thick
1½ cups whole milk, warmed
3 egg yolks
3 tablespoons light brown sugar
½ teaspoon ground cinnamon
2 tablespoons unsalted butter, melted + 2 tablespoons for cooking
¼ teaspoon salt
1 tablespoon vanilla extract
1 tablespoon Triple Sec (optional, can substitute orange juice)
1 teaspoon grated orange zest
¾ cup sliced almonds

For the Topping:
4 tablespoons granulated sugar
2 teaspoons ground cinnamon