First make the milk bread dough. In the bowl of a stand mixer fitted with a dough hook attachment, add the ingredients in the following order: heavy cream, milk, egg, sugar, all-purpose flour, yeast, and salt. Turn on the mixer to “stir,” and knead for 15 minutes, occasionally stopping the mixer to push the dough together. If the dough is sticking to the sides of the bowl, add a little more flour 1 tablespoon at a time until it pulls away from the sides (it should be sticking to the bottom of the mixing bowl, but not the sides). If kneading by hand, extend the kneading time by 5-10 minutes.
Next, cover the dough with a damp towel, and place in a warm spot until the dough has doubled in size (1-2 hours). We proof our dough in a closed microwave with a mug of just-boiled water next to it.
After the dough has doubled in size, put it back in the mixer, and knead for another 5 minutes to get rid of air bubbles.
While that’s happening, melt the butter in a pot or in the microwave. Mix the granulated sugar (not brown sugar) and cinnamon in a separate medium bowl.
Dump the dough on a lightly floured surface, and cut it into quarters. Cut each quarter into 12 roughly equal 1½- to 2-inch (4-5cm) chunks of dough, for a total of 48 pieces.
Place half of the dough pieces into a large bowl. Pour over ¼ cup of butter. Use a rubber spatula to gently toss the dough pieces to coat. Sprinkle over ¼ of the cinnamon sugar mixture and mix. Then sprinkle over another fourth of the cinnamon sugar mixture, and toss to coat. Spread the pieces evenly on the bottom of a 12-cup bundt pan.
Repeat with the remaining half of the dough pieces, ¼ cup butter, and the remaining half of the cinnamon sugar mixture. Make sure the dough is in an even layer. Cover with a clean dish towel and proof in a warm place for 45 mins to 1 hour. The dough should increase in size by 1.5X.
When the dough is nearly done proofing, preheat the oven to 350°F/175°C. When the dough is ready to go into the oven, whisk together the remaining ½ cup butter, dark brown sugar, and vanilla. (You may need to put the butter back in the microwave to melt it again). Pour the butter and brown sugar mixture evenly over the dough.
Place the bundt pan on a baking sheet and bake for 35-40 minutes, or until a thermometer inserted into the center of the bread reads 195°F/90°C.
Let the monkey bread rest for 5 minutes. Place a round serving plate upside-down on the bundt pan, and flip it to turn the monkey bread out. Serve warm!