Instructions

1. Place 4 sticks (1 pound) of the unsalted butter in the bowl of a stand mixer and let sit at room temperature until softened, about 1 hour.
2. Place 1 cup dried currants, 1/2 cup golden raisins, 1/2 cup finely diced candied citron, 1/2 cup finely diced candied orange peel, and 1/2 cup rum in a medium bowl and stir to combine. Cover with plastic wrap and set aside at room temperature until ready to mix into the dough or up to overnight.
3. Place 8 cups all-purpose flour in a large bowl. Measure 1 cup of sugar into a dry measuring cup. Finely grate the zest of 1 large lemon (about 1 1/2 teaspoons)
4. Place 2 cups whole milk in a microwave-safe bowl and microwave until lukewarm (about 90°F), about 1 minute.
5. Add 1/3 cup of the lukewarm milk, 3 packets active dry yeast, 2 tablespoons of the flour from the bowl, and 2 tablespoons of the sugar from the measuring cup to a medium bowl. Stir to combine and set aside until foamy, 5 to 10 minutes.
6. Add the remaining granulated sugar to the bowl of butter. Beat with the paddle attachment on medium speed until light and fluffy, about 3 minutes. Scrape down the sides of the bowl. Beat in 4 large eggs one at a time, beating well after each addition, until combined. Add the lemon zest and 1 teaspoon kosher salt and beat to combine.
7. With the mixer on low speed, carefully alternate between beating in the yeast mixture, remaining lukewarm milk, and remaining flour. The bowl will be very full so start the mixer on low after adding more liquid. Mix until combined and a sticky dough forms.
8. Transfer the dough onto a generously floured work surface and knead until smooth and elastic, 5 to 10 minutes. If the dough is sticking to the board and your hands, gradually add up to 1 cup more flour to the board and your hands as needed. Let the dough rest while preparing the filling.
9. Drain the rum-soaked fruit through a fine-mesh strainer, shaking to remove as much liquid as possible. Transfer to a large bowl. Coarsely chop 5 ounces blanched almonds (1 cup) and add to the bowl with the dried fruit. Split the vanilla bean lengthwise and gently scrape out the seeds into the bowl; stir to combine. Sprinkle with 2 tablespoons all-purpose flour and toss to coat.
10. Gradually add and knead the fruit mixture into the dough a handful at a time, 5 to 10 minutes. The dough will become elastic with a nice sheen.
11. Lightly coat a large bowl with neutral oil or cooking spray. Place the dough inside and flip. Cover with a towel or plastic wrap and let rise in a warm place until doubled in size, about 1 1/2 hours.
12. When ready to form the loaves, lightly coat 2 large baking sheets (at least 18x13-inches) with neutral oil or cooking spray. Melt the remaining 1 1/2 sticks unsalted butter in a small saucepan. (Alternatively, melt butter in the microwave.) Divide the dough into 3 equal portions.
13. Roll out each portion into a 16x8-inch oval. Generously brush with about half of the melted butter. Gently press lengthwise down the center with a rolling pin. Fold the dough in half, bringing one long edge to within 1/2 inch of the opposite edge. Press the fold lightly.
14. Transfer the stollen onto the baking sheets, placing 2 of the loaves on 1 baking sheet. Let rise until puffed and risen a bit, about 45 minutes. It will not double in size. Meanwhile, arrange 2 racks to divide the oven into thirds and heat the oven to 350°F.
15. When ready to bake, brush the stollen with half the remaining melted butter. Bake until golden brown and cooked through, about 45 minutes. Transfer the loaves to wire racks. While still warm from the oven, brush with the remaining melted butter (remelt if needed) and dust with powdered sugar. Let cool completely. Just before serving, dust again with powdered sugar to generously coat.