Method:

• Add yeast and 1 teaspoon sugar to lukewarm water. Let stand 2 to 3 minutes and then stir to dissolve completely. Set the cup in a warm, draft-free place for 3 to 5 minutes, or until the yeast bubbles up and the mixture almost doubles in volume.
• Transfer yeast mixture to a large mixing bowl. Stir in egg yolks, vanilla, lemon peel, salt, and remaining sugar. Add 1 1/2 cups flour, 1/2 cup at a time, mixing constantly. Add enough flour to make a sticky but soft dough.
• Divide the soft butter into 3 pieces. Mix into dough 1 piece at a time. The dough should become heavy and stringy. Roll into a large ball. Slowly add 1/2 cup to 1 cup more flour, mixing constantly. When dough is firm and no longer sticky, knead on floured board for 10 minutes, or until dough is smooth and shiny. Shape into a ball. Place in large clean bowl and sprinkle top with a little flour. Cover bowl and set in a warm, draft-free spot for 30 to 45 minutes, or until has doubled in size.
• Preheat the oven to 400°F. Punch the dough down with your fists. Gently knead in the diced candied citron, the white and dark raisins, and chopped nuts.
• Handle the dough as little as possible after adding the raisins, citron, and nuts or it will discolor. Shape the dough into a ball, place it on a buttered baking sheet, and cut across on the top of the ball.
• Generously butter 1 side of a strip of heavy brown paper about 25 inches long by 5 inches wide. Wrap the paper around the width of the dough, forming a ring around the ball, buttered side towards the dough. Fasten the ends of the paper in place around the dough with string, a pin, or a paper clip and set the dough in a warm place to rise again.
• When the dough has again doubled in size (after about another 15 minutes), brush the top of the dough with melted butter and bake on the middle shelf of the oven for 10 minutes. Then reduce the oven temperature to 350°F, brush the top of bread with more of the melted butter, and bake for 30 to 40 minutes longer. When done, the top should be crisp and golden brown. Brush again with melted butter about 15 or 20 minutes after the baking process begins.
• When the bread is done, cool it on a wire cake rack, removing the paper. To serve, cut the bread into thick wedges.