Bring the eggs, sour cream and melted butter to room temperature. Heat the milk in the microwave or on the stove top until it’s lukewarm, between 120 and 130F (49 to 54C). Pour the milk into a large mixing bowl and sprinkle the dry yeast over the top; let the yeast proof for 5 minutes. After 5 minutes, whisk the yeast and milk together and add the sugar, salt, eggs, egg yolks, sour cream and melted butter. Make sure the butter isn’t too hot, otherwise the heat can kill the yeast. Whisk the ingredients together for a couple minutes until smooth.
Add 2 cups (250 g) of all-purpose flour to the batter and whisk it until it’s smooth; the remaining flour will be added later. Fill a large pot with hot water, not boiling, and place the mixing bowl with the batter over the pot, ensuring that the bottom of the bowl does not touch the water. Let the batter proof for 1 ½ hours and change the water when it cools down completely.
While the batter is proofing, prepare the filling. If using dried fruit, place the fruit into a bowl and top it with warm water. Let the fruit stand and rehydrate while the batter proofs.
Once the batter has proofed, mix in the remaining flour with a spatula or wooden spoon. Once the dough pulls together into a ball, turn it out of the mixing bowl onto the kitchen counter. Sprinkle the counter with a couple extra tablespoons of flour and knead the dough for 4 to 6 minutes, until it’s smooth and elastic. Watch my video recipe for extra tips! Don’t add too much flour; the butter in the dough will grease the counter, preventing the dough from sticking.
Drain any remaining liquids from the dried fruit. Spread the dough into a small square and sprinkle the dried fruit, chocolate or nuts on top, then fold the corners of the dough over. Knead for about 1 minute, adding a sprinkle of flour if necessary, until the dough is smooth.
Roll the dough into a thick log and divide the dough into three even pieces and roll each piece into a ball. Use a kitchen scale for accuracy.
For the traditional round shape, use 6-inch Panettone paper baking molds, or shape a mold using a double layer of parchment paper: line the bottom and sides of two, 6-inch (15-cm) round baking pans with parchment paper reaching about 6 to 7 inches (15-18 cm) up the side. This bread can also be prepared in regular loaf pans lined with parchment paper.
Next, prepare the oven for proofing. Fill a large casserole dish with boiling water and place it at the bottom of the oven. Place the baking sheet with the dough onto the middle rack of the oven and close the door. Allow the dough to proof for approximately 2 hours, or until doubled in size. Change the water every 45 minutes to ensure the oven stays warm and humid.
Baking the Bread:
Once the dough has proofed, remove it from the oven and preheat the oven to 350F/177C. Once the oven is preheated, bake the bread for about 45 minutes. The tops of the bread will start to turn a deep golden brown. I recommend placing a sheet of foil very loosely over the bread around the 30 minute mark to prevent the bread from browning too much.
Once the bread is baked, remove it from the oven and onto a cooling rack to cool.
For Royal Icing:
For the royal icing, place the egg whites into a medium-sized mixing bowl and add just ½ cup of the confectioner’s sugar. Whisk with a mixer on medium speed and gradually add in the remaining confectioner’s sugar, about ½ cup at a time. If glaze becomes too thick, thin it out with a few drops of water. This recipe will make enough to generously coat all three loaves; cut the recipe in half if you don’t want too much glaze.
NOTE: Royal Icing contains raw egg whites. You can also use pasteurized egg whites. Don’t want to use raw egg whites? Make a simple sugar glaze with 2 cups confectioner’s sugar and water or lemon juice. Add a couple tablespoons of liquid at a time and mix to the desired consistency.
Drop spoonful’s of the glaze over the slightly cooled bread; remove the bread from the paper molds if you want the glaze to go down the sides of the bread as well. Sprinkle the top with rainbow nonpareils.
This bread is best enjoyed the day of and the next day. To keep it for the next day, allow the bread to cool completely, then wrap very well in plastic wrap and store at room temperature.