Directions

1. Stir together warm milk, yeast, and 1 teaspoon sugar in a small bowl. Let stand until foamy, about 5 minutes.
2. Combine flour, eggs, egg yolks, honey, vanilla bean paste, lemon zest, orange zest, yeast mixture, and remaining 6 tablespoons sugar in the bowl of a stand mixer fitted with the dough hook attachment. Beat on medium speed until a soft dough forms, about 8 minutes, stopping to scrape the bowl and hook several times. Cover the bowl, and allow the mixed dough to relax at room temperature for 20 to 30 minutes.
3. Add salt to rested dough, and beat on low speed until combined, about 30 seconds. Add butter in 3 to 4 additions, mixing well on medium speed until fully incorporated after each addition. Turn the mixer up to medium-high speed, and beat until a shiny, smooth, strong, elastic dough forms, 4 to 5 minutes. (Dough will be sticky.) Transfer to a buttered or oiled container, cover, and refrigerate 8 hours or overnight.
4. Line 2 rimmed baking sheets with parchment paper; set aside. Transfer dough to a lightly floured work surface. Punch down dough, and divide into 8 (4.3-ounce or 120-gram) portions. Pinch a small piece (about 0.5 ounce or 15 grams) off of each dough portion. Shape the larger piece into a smooth ball with the palm of your hand. Transfer to prepared baking sheets, spacing them at least 3 inches apart. Roll the smaller piece of dough into a small ball. Press a deep indentation in the middle of each large ball with 2 fingers, and nestle 1 small dough ball into each hole. Cover baking sheet with plastic wrap or a clean kitchen towel, and allow buns to rise at room temperature until puffed and almost doubled in size, 1 hour to 1 hour and 30 minutes. In the last 20 minutes of rising, preheat oven to 350°F with racks in upper and lower thirds of the oven.
5. Whisk egg, cream, salt, and sugar together in a small bowl until well combined. Using a fine-bristled pastry brush, brush the buns lightly all over with egg wash.
6. Bake buns in preheated oven until golden brown and an instant-read thermometer inserted into the center registers 190°F, 18 to 20 minutes, rotating baking sheets between top and bottom racks halfway through baking time. Let cool on a wire rack about 20 minutes before serving.