Using a stand mixer, mix together the sugar, butter, salt, water, and yeast. Let it set for 5 minutes until nice and foamy.
Add the flour, 1 cup at a time, until it forms a ball.
Turn onto a floured surface and knead for 8-10 minutes.
Place dough in a greased bowl, cover and let rise until doubled in size (about 30 minutes).
Punch down the dough and divide it into 2 equal balls. Roll into a ball and place side by side on a baking sheet. Cut cross slits in the top. Cover and let rise for another 30 minutes.
Preheat the oven to 400 degrees.
Mix the egg white with the water. Brush over the top of each ball of dough. Sprinkle evenly with salt and rosemary. Bake for 20-25 minutes. It will be golden brown and sound hollow when you tap on the bottom.