Soak the raisins for 15 minutes in lukewarm water. Drain well, pat dry, and mix with the chopped almonds. Set aside.
Make the dough
Combine all dough ingredients except the butter in a mixing bowl with a dough hook. Knead (preferably using a stand mixer) for about 8 minutes until a firm dough forms. Add the butter cubes one at a time and continue kneading until the dough becomes smooth and stretchy, you should be able to pull a thin membrane without breaking the dough.
Let the dough rest for 15 minutes, then knead in filling 1 (raisins and almonds).
First rise and filling 2
Place the dough in a lightly oiled bowl, turning it once so it’s coated with a thin layer of oil. Cover with plastic wrap or a clean towel and let it rise in a warm place (room temperature is fine too) for 60 minutes. It won’t fully double in size.
Meanwhile, knead the lemon zest and egg into the almond paste. Shape into a log and set aside.
Shaping and second rise
Place the dough onto an oiled work surface and gently press out the air. Shape into a loose ball and let it rest, covered, for 20 minutes.
Press the dough into an oval about ¾ inch (2 cm) thick, leaving the short ends slightly thicker. Place the almond paste log in the center. Fold the top short end of the dough over the almond paste, slightly past the bottom edge so it overlaps. Seal gently with the side of your hand and pinch the ends lightly closed.
Flip the dough over (so the seam is underneath) and transfer to a baking sheet lined with parchment. Cover and let rise for 45 minutes at room temperature. It does not need to double in size.
Baking and finishing
Bake the stollen for 35-40 minutes. Bake the first 20 minutes at 350°F /180°C (conventional oven), then reduce the temperature to 320°F (160°C) for the remaining 15-20 minutes.
Place the stollen on a cooling rack. After 10 minutes, brush with melted butter and dust generously with powdered sugar. Let cool completely and dust again before serving.
How to store
Keep the bread in a plastic or paper bag for 1-2 days.