In a large pot of boiling salted water, cook pasta until al dente

In a large high sided skillet or saucepan, heat olive oil over medium high heat

Add in onion and cook until translucent and soft about 5-6 minutes

Add in garlic and cook until fragrant no longer than a minute

Add ground beef and brown. Add in salt and pepper to taste to give the meat flavor

Once the meat is cooked through and browned, drain some of the fat leaving behind about 2 tbsp

Slowly add flour until fat is absorbed and meat is coated. Cook for about 5 minutes until flour is cooked through

Very slowly add room temperature milk mixing into meat mixture. Once all milk is added, simmer until mixture is thickened

While simmering, add in ground mustard and nutmeg

Once mixture is thickened and creamy, stir in cheese until melted

Stir in cooked pasta. Salt and Pepper to taste. Serve immediately.