Combine 2 cups flour, sugar, dry yeast and salt in the bowl of a stand mixer and stir until blended. Combine water, milk and butter in a microwave-safe bowl. Microwave on HIGH in 15 second increments until very warm but not hot to the touch (120° to 130°F. Butter won’t melt completely). Add to flour mixture.
Beat 2 minutes at medium speed, scraping bowl occasionally. Add 1 cup flour; beat 2 minutes at high speed, scraping bowl occasionally. Stir in just enough remaining flour so that the dough will form into a ball.
Knead on lightly floured surface until smooth and elastic and springs back when lightly pressed with 2 fingers, about 6 to 8 minutes. Cover with a towel; let rest for 10 minutes.
Cut dough into 2 equal pieces. Roll each piece of dough into a 12 x 7-inch rectangle using a rolling pin. Brush each piece with melted butter. Stir together the cinnamon and sugar for the filling and sprinkle on each rectangle.
Beginning at short end of each rectangle, roll up tightly. Pinch seams and ends to seal. Place, seam sides down, in two 8-1/2 x 4-1/2 inch loaf pans that have been sprayed with nonstick cooking spray. Cover with towel; let rise in warm place until doubled in size, about 45 minutes.
Bake in preheated 400ºF oven for 20 to 30 minutes or until golden brown. Remove from pans by running a knife around the edges and invert onto wire rack.