When it comes to dressing up ice cream, mix-ins go a step beyond exotic toppings such as crushed candies or ground nuts, because mix-ins such as chocolate-covered raisins or crushed cookies are actually worked into softened ice cream right before your eyes.
Brownies merit serious mix-in consideration. If they are cut into small cubes and frozen before being added to the ice cream, they will not disintegrate, as demonstrated in this Mocha Brownie Chunk Ice Cream.
Once the brownies are cut up and frozen, preparing the ice cream custard base takes only 20 minutes. The custard requires no on-the-stove cooking since it is made instantly in the food processor.
The technique is identical to that used to make custard sauce or creme anglaise. Simmering half and half, in which instant espresso coffee and sugar have been dissolved, is added to egg yolks during processing. Since egg yolks cook at 160 to 170 degrees Fahrenheit, the simmering liquid and yolks thicken almost as soon as they are thoroughly combined.
Ground semisweet chocolate then is added to the hot custard mixture and briefly processed (this replaces on-the-stove melting). Simply transfer the custard to a metal mixing bowl, place the bowl over ice, and as soon as the custard is cool, the ice cream is ready for churning.
For best results, the frozen brownies should be added to partly frozen ice cream.
MOCHA BROWNIE CHUNK
2 ounces semisweet chocolate, in 1/2-inch chunks
1/4 cup instant espresso coffee
3/4 cup sugar
2 cups half and half
3 egg yolks
1 cup whipping cream
3 tablespoons coffee liqueur
1 1/2 tablespoons vanilla
1/2 pound brownies, cut in 1/4-inch chunks, frozen
Insert metal blade in dry food processor. Drop chocolate chunks through food chute and process to mince, then set chocolate aside.
Mix instant coffee, sugar and half and half in medium saucepan. Stir well and heat to simmering. Place egg yolks in processor container. With machine running, add simmering coffee mixture through food chute within 20 seconds. Add ground chocolate and process 20 seconds or until chocolate dissolves. Transfer mixture to bowl and stir in whipping cream, liqueur and vanilla. Set over ice or refrigerate until thoroughly chilled.
Transfer mocha custard to ice cream freezer. Follow manufacturer's directions and churn until half frozen. Add frozen brownie pieces and continue churning until ice cream is ready. Makes 4 to 6 servings.