Step 1

Preheat oven to 400 degrees. Set a large pot of salted water to boil and butter an 8-inch square baking dish. In a small bowl, combine tomatoes, olives, and oregano.

Step 2

Cook pasta 2 minutes less than package instructions; drain pasta and return to pot. Meanwhile, melt butter in a medium saucepan over medium. Add garlic; cook until fragrant, 1 minute. Add flour and cook, stirring constantly, 1 minute. Whisk in milk and bring to a boil. Reduce heat to medium-low; simmer, whisking constantly, until sauce thickens, 3 minutes. Remove from heat; whisk in 4 ounces feta. Stir in tomato mixture. Season with salt and pepper. Pour mixture over pasta; stir to combine.

Step 3

Pour pasta mixture into dish and top with 4 ounces feta. Bake until sauce is bubbling and cheese begins to brown, 20 to 25 minutes.