Eat the yellow snow!
OK, that was a little gross, but if you've just had a late snowfall, you can make yourself a treat that's almost as good as ice cream and twice as much fun to make. Plus, you don't have to wait all that time to get the custard mix to freeze as nature has done all the work for you.
Basically, snow cream is plain old fresh snow flavored with a little dairy, sugar, and vanilla. Because it depends on fresh clean snow, I wouldn't necessarily try this recipe downwind from an incinerator or crematorium (yeek).
Why does snow lend itself to this treatment? Think about ice cream? Ice cream is basically a collection of tiny frozen crystals of milk/egg/vanilla/sugar beaten together with air. Snow is fluffy frozen water crystals, so we just need to add the rest of the flavors to it to get an near-instant dairy treat.
Snow has different ratios of water to air, depending on the temperature outside, the winds, and the average velocity of an unladen swallow. For that reason, all I can give you here is guidance and not a hard formula. The inspiration for this recipe comes from my in-laws, who starting making snow cream as kids growing up.
A bunch of fresh snow. Maybe a gallon's worth (it will reduce in volume as you mix it)
Milk or cream (not much, maybe a cup per gallon)
Sugar (1/2 cup or so per gallon, or to taste)
Vanilla - tablespoon or two per gallon
The important thing is to get clean snow. Ideally, "harvest" your snow off the very top of the pile while it's still coming down, and only take the freshest stuff. The last thing you want to do is eat dirt with your tasty treat.
Add the sugar and vanilla a little at a time and mix lightly with a big spoon. You should be using a folding motion rather than a whisking or beating motion to mix the ingredients. Add a little milk or cream and repeat until the snow cream tastes the way you'd like it to taste - a little thinner than ice cream, but quite tasty.
Be especially careful with the milk as it will liquify the snow most rapidly. If possible, mix everything outside under the open sky where its chilly enough to keep the snow mostly intact.