1. Dissolve sugar in lukewarm water. Sprinkle with yeast and let sit for 8 to 10 minutes, until foamy. Stir with a spoon.
Melt butter in a small saucepan.
2. Add Liberté yogurt and Liberté Quark cheese while stirring. Heat until lukewarm. In a large bowl, sift 2 cups (500ml) flour, the baking soda, the sugar and the salt. Add in dissolved yeast.
3. Then add the yogurt-cheese mix and stir well.
4. Gradually add the remaining flour, which will produce a fine and sticky dough. Knead the dough on a flour-sifted cooking plate for about 5 minutes and place it in a greased bowl.
5. Cover with cellophane paper and let rise, at room temperature, for about an hour. The dough should double in volume. Deflate with fist.
6. Spread the dough in a rectangular shape of 22 X 30 cm on a slightly floured cooking plate.
7. With the biggest sides, roll the dough like a sausage and seal each ends by pressing with your fingertips.
8. Place in a greased 22 x 12 x 7 bread mold, making sure to put the seam at the bottom. You can put the bread on a cookie plate. Cover with a cloth and let rise for about an hour. Should double in volume.
9. Bake at a temperature of 375 F (190 C) for 25 to 30 minutes, until golden. When patted with fingers, the bread should have a hollow sound. Unmold immediately and let cool on a grid.