In certain parts of Germany, you commonly find recipes for stollen made with cottage cheese. It gives the dough a wonderful creamy color and keeps the bread from drying out.
In a small bowl, add the yeast to the lukewarm water and set aside. Put the cottage cheese, sugar, butter, and eggs in the bowl of a food processor. Add the warm milk, and puree. Pour into a large bowl. Stir in the vanilla, zest, salt, and dissolved yeast. Add 3 cups of the flour to make a sponge, and beat with a wooden spoon for 100 strokes. Cover and set aside for 15 minutes. Add enough of the remaining flour, about ⅓ cup at a time, to make a soft, kneadable dough. Turn the dough out onto a floured surface and knead for 8 minutes, using enough of the remaining flour to keep the dough from sticking. Place the dough into a lightly oiled bowl, turning the dough to coat its surface. Cover the bowl with plastic wrap and set aside in a warm spot until doubled, 1-½ to 2 hours. Mix together the raisins and walnuts in a bowl and set aside. Flour your work counter, and turn the dough out without punching it down. Roll the dough into a large rectangle about 1 inch thick. Spread the raisin-and-nut mixture over the dough, pressing down gently. Roll up the dough like a carpet, lengthwise. Cut into 3 equal sections. Roll each into a ball. With seam side down and loosely covered, let rest for 10 minutes. Roll each ball into an oblong strip about ½ inch thick. Fold each strip not quite in half, lengthwise. (They’ll look like giant pairs of lips, the upper one set back about 1 inch from the lower.) Place one stollen on a lightly buttered baking sheet and two on another, evenly spaced. Cover loosely with plastic wrap and set aside in a warm spot until it begins to swell but before it doubles, about 35 to 45 minutes. Preheat oven to 350 degrees F. Bake the stollen for 45 minutes; the surfaces will become quite dark. Transfer to a rack and immediately brush top and sides with melted butter. When cool, dust amply with confectioners’ sugar. Wrap in foil, then slip into plastic bags. Refrigerate until serving time.