Warm the milk in a small saucepan until it bubbles, then remove from heat. Let cool until lukewarm.
Dissolve the yeast in the warm water. Stir in the lukewarm milk, sugar, salt, cardamom, 4 eggs, and enough flour to make a batter (approximately 2 cups). Beat until the dough is smooth and elastic. Add about 3 cups of the flour and beat well; the dough should be smooth and glossy in appearance. Add the melted butter or margarine, and stir well. Beat again until the dough looks glossy. Stir in the remaining flour until the dough is stiff.
Turn out of bowl onto a floured surface, cover with an inverted mixing bowl, and let rest for 15 minutes. Knead the dough until smooth and satiny. Place in a lightly greased mixing bowl, and turn the dough to grease the top. Cover with a clean dishtowel. Let rise in a warm place until doubled in bulk, about 1 hour. Punch down, and let rise again until almost doubled.
Turn out again on to a floured surface, and divide into 3 parts. Divide each third into 3 again. Roll each piece into a 12 to 16 inch strip. Braid 3 strips into a loaf. You should get 3 large braided loaves. Lift the braids onto greased baking sheets. Let rise for 20 minutes.
Brush each loaf with egg wash and sprinkle with sugar.
Bake at 400 degrees F (205 degrees C) for 25 to 30 minutes. Check occasionally because the bottom burns easily.