Instructions

1. Position a rack in the lower third of the oven, and preheat to 325 degrees F. Grease your Bundt pan and dust with flour.
2. Sift the flour, hot chocolate mix, and salt into a medium bowl. Set aside.
3. In another small bowl whisk together the eggs, sour cream, and vanilla.
4. Beat the butter and sugar in a large bowl with an electric mixer on medium-high speed until smooth. Continue to beat the butter mixture until light and fluffy, about 5 minutes. Scrape down the bowl as needed.
5. Reduce the mixer speed to low. Gradually beat in half of the flour mixture. Then, beat in the egg and sour cream mixture for about 30 seconds. Then, beat in the rest of the flour mixture until everything is combined. (Take care not to overmix.)
6. Fold in the chocolate chips, if desired. Spoon the batter into the prepared pan.
7. Bake until a toothpick inserted in the center comes out clean and the top springs back when lightly pressed, 40-50 minutes.
8. Let the cake cool in the pan for a few minutes, then invert it onto a serving plate and let it cool completely on a rack.
9. For the glaze, whisk together the powdered sugar, melted butter, and hot chocolate mix (and espresso powder if using). Add milk, one tablespoon at a time, until consistency is thin enough that it falls in ribbons off of whisk but holds its shape for several seconds before melting back into the bowl.
10. Pour over your cooled Bundt and allow to set.