More to explore:
make ice cream without an ice cream maker and not in a plastic bag
Homemade ice cream without the ice cream maker.
Ice Cream w/o a Machine (with links to Serious Eats directions [I've pinned elsewhere], compared to that and Lebovitz's methods this one requires less stirring and, thus, less hands-on time; what you need: ice cream base/mix [has links to recipes], large mixing bowl and a smaller one that can fit inside, chopped ice, rock salt, hand mixer, towel)
18 Frozen Treats You Can Enjoy Without an Ice Cream Maker — Summer Recipes from The Kitchn
How To Make Ice Cream Without an Ice Cream Machine: An Easy, Foolproof Method... Spiced coconut milk icecream