Substitute for Sweetened Condensed Milk

This requires a safe milk substitute such as soy or rice, I bet potato would work too?

I've not tried this other than in pumpkin pie filling, but a 14 oz can of sweetened condensed milk can be subbed with 1/2 cup maple syrup and 1/2 cup soy milk (or rice milk). I've also used rice milk and subbed the maple syrup with brown sugar and water.