Preheat oven to 350. Spray a donut pan with non-stick cooking spray.
In a medium bowl, whisk together flour, sugar, unsweetened baking cocoa, baking powder, baking soda, and salt.
In a small bowl, whisk together milk, coffee, butter, egg, and vanilla extract. Add wet ingredients to dry ingredients and stir until just combined. Stir in white chocolate chips.
Transfer batter to a pastry bag or plastic bag with corner cut off. Pipe batter into donut pan filling each cavity about ⅔ full.
Bake for 8 minutes. Transfer pan to a wire rack to cool.
While donuts are cooling, stir together all ingredients for the glaze until smooth. You may need to add up to another ½ teaspoon of milk to reach desired consistency. Dip tops of donuts into glaze.
Allow glaze to harden and serve.
Recipe by A Kitchen Addiction at https://www.a-kitchen-addiction.com/mocha-white-chocolate-chip-donuts/