Sometimes two great tastes don't taste great together. Sometimes they wreak havoc with each other, throwing off balance and nuance, making a mash-up that's less interesting and delicious than either ingredient alone. All too often coffee and chocolate are victims of this abuse.
Do it right and coffee's bitter/roasted flavors accentuate those in chocolate, while cocoa adds buttery body to the coffee. Do it wrong and you have something too-bitter, too-roasted, too-sweet, or, most commonly, just plain bland.
So if you're going to make mocha ice cream, keep your priorities in check. Do you want something deep and dark, intensely chocolatey but more bitter? Or do you want a milder exploration of coffee and chocolate's common elements, with the volume turned down so the subtleties play out? Either way, go in with a game plan and pick your ingredients accordingly.
This ice cream is of the latter frame of mind, milky but decidedly chocolate-forward like a good rocky road, with coffee there to cut the sweetness and clean up chocolate's loose fatty edges. It's a cooler, cleaner chocolate than your average scoop, but still kid-friendly.
Your mileage may vary, but I prefer to leave the medium-size coffee grinds right in the ice cream. They add bursts of coffee flavor and a nice chewiness, like sprinkles, but with less wax and sweetness. I have to insist on the cashews, which function like chocolate chips and nuts all in one. They have a smoother snap than almonds and they add one more dimension of roasted, buttery flavor to the ice cream. If you have smoked cashews on hand, all the better, but even plain ones will have you re-thinking your go-to nut for mixing into ice cream.