Instructions

  1. Preheat oven to 375°F.
  2. Melt butter in a small saucepan over medium-high heat. Add flour, and cook stirring constantly with a whisk for a couple of minutes, until bubbly and flour has a chance to cook a bit. Stir in the thyme. Gradually add milk, stirring with a whisk; cook over medium heat until slightly thick (about 3 minutes), stirring constantly.
  3. Stir in the Gorgonzola; cook 3 minutes or until cheese melts, stirring constantly. Stir in salt and pepper. Remove from heat.
  4. Arrange one-fourth of potatoes in bottom of a 13 x 9-inch baking dish coated with cooking spray; spoon 3/4 cup sauce over potatoes. Repeat layers twice; arrange remaining potatoes over sauce. Sprinkle with Parmigiano-Reggiano.
  5. Cover and bake at 375°F for 30 minutes. Uncover and bake an additional 30-40 minutes or until potatoes are tender and golden brown on top. Remove from oven; let stand for 10 minutes before serving.