In a large mixing bowl, combine 2 and 1/4 cup all-purpose flour, sugar, salt and active dry yeast. Whisk well.

In a microwave-safe bowl, microwave butter, milk and water until the butter melts. The temperature of the mixture should be between 110-115 F. Re-heat in the microwave when necessary.

Add the butter mixture to the dry ingredients in the mixing bowl. Stir the mixture using a wooden spoon until incorporated. Add the egg and stir. Add some of the reserved flour gradually while stirring until the mixture turns into a soft dough that gathers in the center of the bowl. You may not need all the flour.

Turn the dough onto a floured board and knead for 6-12 minutes, until it is smooth and elastic. Let the dough rest for ten minutes in a bowl, covered.

Roll the dough using a rolling pin into a 14x10 inch rectangle. Sprinkle garlic powder all over the dough. Sprinkle the cheeses and the scallions.  Starting on the long edge, roll the dough into a tight log. Using a sharp knife, slice the log in half vertically, starting about an inch below the upper edge, leaving the top edge uncut.  Gently rotate the divided logs so that the cut side is facing up.

Begin braiding the dough by placing one side over the other, repeating the braiding pattern until you reach the end of the log. Gently lift the braided dough and place it inside a greased 9x5 inch loaf pan. 

Let the shaped dough rise for 1 ½ hours, covered with a clean towel. The braided dough should be soft and puffy.

Position a rack one level lower than the middle position in the oven. Preheat oven to 350 F. Once the oven reaches 350 F, place the loaf pan in the prepared rack. Bake the loaf for 43-46 minutes, lossely covering the loaf with foil at the 25 minute mark. The top is nicely golden and a thermometer inserted at the center of teh loaf should read 200 F. Let the loaf cool on a wire rack completely.