To the same skillet, add the butter and shallot, cooking until fragrant, about 3 minutes. Add the garlic and orzo, cooking until slightly golden, 2-3 minutes. Add the wine and de-glaze the pan. Add 1 ½ cups water. Bring to a boil and cook 3-5 minutes, then add the cream, mustard, Parmesan, spinach, and sun-dried tomatoes, stirring until the spinach has wilted. Slide the chicken back into the pan and bake uncovered for 10-15 minutes, until the chicken is cooked through.