In a large bowl, whisk together flour, ground nuts, baking powder, salt, cardamom, nutmeg, and orange zest until combined. Add cubed butter, and using your fingertips, rub butter into flour mixture until there are no more lumps of butter and mixture resembles wet sand. (There should be no clumps of zest; it should be evenly distributed throughout.) Add granulated sugar, cranberries, and candied peel, and toss well until combined.
In a medium bowl, whisk together quark, eggs, rum, and extracts until smooth. Pour over flour mixture, and using a fork or wooden spoon, fold and blend until dry ingredients are moistened and a dough forms.
Scrape dough out onto a lightly floured surface, and knead until dough is smooth, elastic, and no longer sticky, 10 to 15 minutes, adding extra flour as needed.
Preheat oven to 350°F (180°C). Line a baking sheet with parchment paper.
Shape dough into a 11-inch oval with slightly tapered ends. Make a deep, exaggerated indentation down long side of dough about one-third of the way in. (If the indentation is not deep enough, it will be lost in baking.) Place on prepared pan.
Bake for 45 minutes. Reduce oven temperature to 325°F (170°C), and bake for 15 minutes more, loosely covering with foil to prevent excess browning, if necessary. Immediately brush entire top and sides of hot loaf with softened butter. Generously dust with confectioners’ sugar.