Food Network shares how to make a roux, which is the base to thicken sauces and soups. It’s made from equal parts butter or oil and flour. For a light roux, melt butter over medium-low heat, add flour and stir constantly with a wooden spoon in a figure eight for even cooking. In three to five minutes the light roux will be slightly puffed. It can be used in white sauces like white pepper gravy or bechamel sauce. A brown roux is perfect for gravy and will need to cook for six to seven minutes. Dark roux is great for Cajun and Creole recipes and needs to cook for eight to 15 minutes. Keep in mind that the longer a roux cooks, the less thickening power it will have. Always let your roux cool slightly before adding another liquid, like stock or milk, then whisk and simmer to your desired thickness.
Add oil to large skillet over high heat. Add ground beef and saute, breaking up the meat into crumbles as it cooks. Add garlic, oregano and chili flakes and cook a couple minutes. Add tomatoes and season, to taste, with sugar, salt and pepper. Simmer for 10 minutes.
For the bechamel:
In a large saucepan melt butter over medium-high heat until bubbling. Add onions and saute until translucent. Sprinkle with flour, stirring constantly and cook until the mixture begins to thicken. Gradually whisk in the wine, if using, and then gradually whisk in the milk and nutmeg and cook until smooth, thick and creamy. Combine the meat sauce and pasta, and then pour in half the pasta mixture. Spoon half the bechamel over the pasta and top with half the cheese. Repeat with the remaining ingredients. Bake 30 to 45 minutes until browned and bubbly.