Process 1 (6-ounce) container raspberries in the container of a blender until smooth. Strain through a fine-mesh sieve into a small bowl. (This makes about 1/3 cup purée.) Heat milk and 1/3 cup sugar in a medium saucepan over medium heat until steaming. (Do not boil.) Whisk together egg yolks, cornstarch, and remaining 1/3 cup sugar in a medium bowl until smooth. Whisk in hot milk mixture. Return mixture to saucepan; cook over medium heat, whisking constantly, until mixture starts to boil. (Mixture will be thick.) Boil, whisking constantly, until cornstarch flavor has cooked out, 2 to 3 minutes. Remove from heat, and whisk in raspberry purée, butter, ½ teaspoon lemon juice, and red food coloring. Strain through a fine-mesh sieve into another medium bowl. Cover with plastic wrap, pressing wrap directly onto surface of pudding to prevent a skin from forming. Refrigerate until cold, 3 to 4 hours. Whisk cold raspberry pudding until smooth. Toss together banana slices and remaining 1 teaspoon lemon juice in another small bowl. Spoon ¼ cup raspberry pudding into bottom of 6 (8-ounce) glass containers. Top with half of a graham cracker, breaking into bite-size pieces. Top with 4 banana slices and 3 fresh raspberries. Top with ¼ cup Whipped Cream. Repeat layers one more time in each container. Refrigerate until ready to serve. Garnish with graham cracker crumbs, if desired.