Cook pasta according to package directions, drain. Preheat oven to 350 degrees F.
- Melt 3 Tbsp butter in a large pot; add flour and cook for 2-3 minutes. Add chicken broth, whisking to blend. Bring to a boil and allow to thicken slightly. Remove from heat. Add cheddar cheese, and 1 1/2 cups of the crumbled feta, stirring to blend. Stir in the yogurt. Add the cooked pasta, and stir to coat.
- Transfer to a 3 qt baking dish. Melt remaining butter, stir in panko crumbs, oregano and remaining feta, and sprinkle it over the top.
- Bake in the preheated 350 degree F oven for 30 minutes or until hot and bubbly.
Tip: Recipe Tip – Place the mixture into two smaller sized baking dishes, and save for another night.