I've been on an ice cream making kick lately. I can't help it. It's summer and it's hot, and my ice cream maker is still relatively new. I find that the best ice cream starts with a custard base. It doesn't freeze up as hard as a base with no eggs in my experience, and I also find it has a smoother, creamier mouthfeel.
Sweet Cream Custard Base
1 qt half and half
1 c sugar
4 eggs (or 8 egg yolks)
a pinch of salt
1) Stir together 2 c half and half, sugar, and salt in a saucepan over low to medium-low heat until the sugar is completely dissolved.
2) Whisk together the eggs and slowly whisk in the half and half mixture until you've mixed in about a third, then pour it back into the saucepan. This is called tempering and will prevent the eggs from scrambling when added to the milk.
3) Cook over low to medium-low heat, stirring and scraping the bottom constantly until the custard thickens. It should coat the back of a spoon, and when you run your finger across the spoon, it should leave a track that the custard does not run into.
4) Once you've reached the correct consistency, strain the mixture into the rest of the half and half to stop the cooking.
5) Either chill over an ice bath or in the refrigerator overnight. The colder the mixture is before you freeze it, the better. You will have a better consistency because the ice crystals will be smaller.
6) Freeze according to manufacturer directions on your ice cream maker. I have a Cuisinart ice cream maker with a freezable core (it should be in the freezer at least 24 hours before freezing). I let it go for at least 20 minutes before I check it. I look for the ice cream to be heaping up in a spot before I call it finished. It should be the consistency of soft serve.
7) Put the ice cream in the container of your choice and put it in the freezer. It should be at the right consistency in a few hours.
Vanilla - steep a vanilla bean in the milk and sugar at the beginning of the process, or add a teaspoon or two of vanilla extract just before freezing.
Chocolate - add 1/2 c of cocoa powder to the half and half before adding sugar and salt. Let it get completely incorporated before adding sugar and salt.
Mint Chocolate Chip - steep up to 3 cups of mint leaves in the half and half and strain before adding sugar and salt (I'd suggest using more like 1 cup. I find 3 cups far too minty, but this is the amount I've seen in most recipes), or add a teaspoon of peppermint oil just before freezing. Add the chocolate chips near the end of the freezing process. Keep the chocolate chips cold.
Strawberry - Halve the above recipe. Use 1 c half and half and 1 c cream instead of 2 c half and half. Once the custard is ready, add it and a 10 oz package of frozen strawberries or a pint of fresh, hulled strawberries to a blender and puree.
photo via Flickr user laffy4k