Over med-low heat, warm up 1 cup of milk. Stir in gelatin until it is dissolved. Take the milk off of the heat.
Add another 3 cups of milk. Add vanilla, sugar, and salt. Mix well, then cover it with aluminum foil and put in the freezer.
Crush up strawberries. Let it sit in the fridge.
Let the milk freeze for 3 hours. It shouldn't be completely frozen, just sort of slushy. Mix the strawberries into the slushy milk.
Put the whole thing back into the freezer for another 2+ hours (until frozen).
Take it out 10 minutes before you want to eat it to let it soften up a bit.
