Spray a small loaf pan with cooking spray. In a big bowl or measuring cup, combine cherry Jell-O with boiling water and whisk to combine. Let it sit for 2 minutes, then whisk in 1/2 cup vodka. Set aside.

In a separate large bowl or measuring cup, combine a cup of vodka with gelatin and let it sit for 2 minutes. Add water and stir until the gelatin dissolves completely. Pour in sweetened condensed milk and whisk to combine.

Pour half of the red mixture, about a cup's worth, into the loaf pan. Freeze the pan for 20 minutes until it's firm, then add a cup of the white mixture. Repeat twice more, letting the layers firm for 20 minutes between each addition until you have four layers. Refrigerate the pan for 4 hours or overnight. Remove the mixture from the pan and cut it into squares. Top with crushed candy canes and serve.