In a small bowl, combine currants, raisins, and rum. Let soak for at least 4 hours and up to 8 hours. Drain fruit, reserving liquid. Fruit and reserved liquid may be stored separately in the refrigerator in airtight containers.
Preheat oven to 350 degrees with rack in center. Spread almonds in an even layer on a baking sheet. Bake until golden brown and fragrant, 10 to 12 minutes. Let cool.
In the jar of a blender, combine ricotta, eggs, vanilla and almond extracts, and 3 tablespoons of the reserved soaking liquid; blend until smooth. Set aside.
In a medium bowl, whisk together flour, sugar, baking powder, cardamom, mace, and salt. Add chilled butter; cut in butter until mixture resembles coarse meal. Set aside.
In a large bowl, combine fruit, almonds, and lemon peel; stir in ricotta mixture until combined. Add flour mixture, mixing until just incorporated.
Turn dough out onto a lightly floured work surface; knead until smooth. Divide dough in half; cover half the dough with a clean kitchen towel.
Using a lightly floured rolling pin, roll out dough to a 9-by-8-inch oval. Place rolling pin just off center lengthwise, and press gently to form a slight indentation. Brush top surface of dough with 1 tablespoon melted butter. Carefully fold dough lengthwise along indentation, leaving 1 inch of the bottom edge exposed. Transfer to a baking sheet lined with parchment paper or a nonstick baking mat; repeat with remaining dough. Bake until golden and a cake tester inserted in the center of each comes out clean, about 45 minutes. Transfer to a cooling rack; let cool completely.
Wrap cooled breads in parchment paper-lined heavy aluminum foil. Let stand at room temperature for 2 days.
Preheat oven to 350 degrees. To serve, bake wrapped breads until heated through, about 15 minutes. Brush each loaf with 2 tablespoons melted butter; sprinkle generously with vanilla sugar, if using. Serve with whipped cream cheese, if desired.