Thaw bread dough according to package directions. On a lightly floured surface, stretch and roll dough into a 15x9-inch rectangle. Transfer to a 15x10x1-inch baking sheet coated with cooking spray. Cover and let rise in a warm place for one hour.
Heat oven to 350°F.
Cook onion and garlic in oil in a skillet over medium heat for 3 minutes or until tender. Add spinach; cook for 1 minute or until wilted. Transfer to a large bowl. Add cheddar cheese, ricotta, one beaten egg, basil, and salt; mix well.
Arrange the sun-dried tomatoes lengthwise down the center of the dough leaving three inches on each side and an inch at the end. Evenly arrange the spinach mixture on top of the tomatoes. Fold the short edges over the filling. Using a knife or kitchen shears, cut 1-inch wide strips down the length of the dough to within 1/2-inch of the filling. Cut the same number of strips on each side. Cross strips over the filling, alternating each side, to make a braid effect. Brush dough with the remaining beaten egg.
Bake for 25 to 30 minutes or until golden brown. Cool for 10 to 15 minutes before slicing. Serve warm.