1. Warm the half-and-half, sugar and salt in a medium saucepan. In a large bowl, whisk together the heavy cream, vanilla and malt powder and set a mesh strainer on top.
2. In a separate medium bowl, whisk together the egg yolks. Slowly pour the warm mixture in the egg yolks, whisking constantly, then scrape the warmed egg yolks back into the saucepan.
3. Stir the mixture constantly over medium heat with a heatproof spatula, scraping the bottom as you stir, until the mixture thickens and coats the spatula. Pour the custard through the strainer and whisk it into the malted milk mixture. Stir until cool over an ice bath.
4. Chill the mixture thoroughly in the refrigerator, then freeze it in your ice cream maker according to the manufacturer's instructions. As you remove the ice cream from the machine, fold in the chopped malted milk balls.