This is a Bread that I Developed for a Class in whole grain baking that I taught at King Arthur’s Baking Education Center. Quark is a cultured soft cheese, commonly used in German baking. It not only provides a bit of acidity, it also contributes some smooth lactic notes to the finished loaves (as does the milk powder in the formula). Substitutes for quark include crème fraîche, fromage blanc (a French cultured cheese similar to sour cream), yogurt, or ricotta (although ricotta will not add tanginess). With only 20 percent of the flour being acidified, the comparatively mild sourness contrasts nicely with the flavors of the milk powder and quark. I particularly like these loaves when they are topped with rye chops, which one does by pressing the tops of the shaped loaves into a damp cloth and then into a tray of chops. They not only look interesting, the chops also bring a nice crunch to the eating quality of the bread.