Begin melting the chocolate along with ¼ cup of the milk in the top of a double boiler. Stir until chocolate is melted, then add the cocoa powder and gradually whisk in remaining milk. Whisk until smooth and remove from heat.
In a mixing bowl, whisk the eggs until light, then gradually whisk in the sugar. Pour in the cream and vanilla and whisk to blend.
Pour the chocolate mixture into the cream mixture and whisk until blended, then whisk in the malt powder. Do your best to whisk out lumps of malted milk powder, but don't worry too much because they'll disappear during the freezing process. Cover and refrigerate for 1 to 3 hours (or overnight) until very cold.
Transfer to your ice cream maker and freeze using the manufacturer's directions.