Adding only as much flour as necessary to prevent sticking, knead the bread dough until smooth, about 5 minutes. (The gluten in rye is more fragile than in wheat. It needs a resting time to recuperate and reform and does not need as lengthy or vigorous a kneading).
Form the dough into a smooth ball and place it in a buttered bowl, turning it to coat all sides with the butter. Cover it and let it rise in a warm spot until doubled in size, about 2 hours.
Punch the dough down, gently knead it for one minute, and divide it into two parts.
Form each half into a round loaf and place the loaves in two lightly buttered 9-inch round cake pans or on a large, buttered baking sheet.
Press a hole through the center of each loaf to give it a traditional shape if you wish. Cover and let rise until almost doubled in size, about ½ hour.
Preheat the oven to 375 °F.
Brush the loaves with water and gently puncture the surface all over with the tines of a fork, in a design if you wish.
Bake for about 30 minutes or until the bread is golden brown and sounds hollow when tapped on the bottom.
While it is hot, brush it with butter to glaze, and then let it cool on a rack.