Warm 3 cups milk, 1 cup cream, and 1 Tbsp. of gelatin together in a saucepan until the gelatin is dissolved. Whisk the mixture a bit to incorporate the gelatin. You do not need to heat the milk very high. We use fresh milk to make our ice cream, so we watch the temperature closely. Usually around 100F/38C is enough to dissolve the gelatin.
Add 1/2 - 3/4 cups of sugar to warm milk mixture and stir to dissolve. Whisk in flavor additives like 1/2 cup of cocoa powder or 1 Tbsp. of vanilla, if using.
Pour the mixture into the previously frozen bowl that fits into the unit. I use a 2 quart bowl. If yours is smaller, only use half this recipe amount and freeze the rest later.
Put the paddle inside the bowl, place the lid on top and turn the unit to on. Wait about twenty minutes, or until you hear the unit start to slow down its rotations. You'll be able to see through the top to determine if the ice cream is frozen to your satisfaction. Put in other additives, if you have them and allow them to mix in for a few minutes.
Remove the ice cream immediately from the bowl or you'll have a layer of ice cream freeze hard to the side of the bowl. Use a soft spatula so you don't scrape the sides of your bowl. Serve immediately.
If you need to store your ice cream, line a bread pan with parchment paper and empty your ice cream bowl into it. Freeze the ice cream in the pan. Pull the parchment paper out with your frozen ice cream inside, wrap up and put into a freezer bag or suitable container. I have some glass containers I use when I store my ice cream. Honestly, we eat it up right away most of the time.
Remove the ice cream from the freezer 30-60 minutes before you need to eat it so it can start to soften. This is very dependant on how hard it has frozen.