Tres Leches Bread Pudding

Name: Tres Leches Bread Pudding
Ingredients: Nonstick spray; 2 1/4 cups whole milk; 1 (14-ounce) can sweetened condensed milk; 1 (12-ounce) can evaporated milk; 1/2 cup sugar; 1 tablespoon vanilla extract; 1 teaspoon ground cinnamon; 1 teaspoon kosher salt; 9 large egg yolks; 1 loaf challah bread, cut or torn into 1-inch pieces (stale is best); 3/4 cup slivered almonds, toasted; Cinnamon Sugar Sauce, recipe follows; Freshly whipped cream, for serving; 3/4 cup sugar; 8 tablespoons (1 stick) unsalted butter; 1/2 cup buttermilk; 1 tablespoon light corn syrup; 1 teaspoon vanilla extract; 1/2 teaspoon ground cinnamon; Pinch salt; 1 teaspoon baking soda