I have a $40 krups that works just fine on these:
2 ½ cups milk
4 egg yolks
¾ cup sugar
Extract(s) of your choice
Cook the milk with half the sugar, when it's hot add your extract (how much really depends on the flavor and how you like it, so taste it).
Meanwhile, beat the eggs and the other half of the sugar, until pale, and slowly add in warm milk to eggs/sugar and beat. Cook again, not quite a boil.
Cool, chill, then put through your machine.
2 ounces fine-quality bittersweet chocolate (not unsweetened)
2 1/4 cups whole milk
1/3 cup heavy cream
3/4 cup minus 2 tablespoons superfine granulated sugar
1 cup unsweetened cocoa powder
4 large egg yolks
Coarsely chop chocolate. In a 2-quart heavy saucepan bring milk, cream, and about half of sugar just to a simmer, stirring until sugar is dissolved. Remove pan from heat and add cocoa powder and chocolate, whisking until chocolate is melted and mixture is smooth.
In a bowl with an electric mixer beat yolks and remaining sugar until thick and pale. Add hot chocolate mixture in a slow stream, whisking, and pour into saucepan. Cook custard over moderately low heat, stirring constantly, until a thermometer registers 170°F. (Do not let boil.) Pour custard through a sieve into a metal bowl set in ice and cold water and cool. Chill custard, covered, until cold, then put it through your machine.
I have also used cinnamon chips in this and it was wonderful (I just skipped the cocoa powder and reduced the sugar).