Creamy Ricotta Beef Stuffed Shells Pasta

In a skillet, saute the ground beef with the onion and garlic until the meat is cooked through and the onion is soft. Season with salt, pepper and oregano.
Remove the skillet from the heat and let it cool. Then add the ricotta, egg, parmesan and additional seasonings (to taste) and mix well.
Scoop the mixture into a piping bag or spoon to fill the pasta shells.
Prepare the sauce:

In a small saucepan, melt the butter, add the flour and cook, stirring constantly, for about 1-2 minutes to make a roux.
Slowly stir in the milk and cream, stirring constantly to avoid lumps. Bring the sauce to a boil until it thickens.
Add the mustard, parmesan and nutmeg and season with salt and pepper to taste.
Fill the pasta:

Carefully fill the cooked pasta shells with the beef and ricotta mixture.
Bake:

Cover a baking dish with some sauce, arrange the stuffed pasta shells on top and pour the remaining sauce over it.
Sprinkle with some extra parmesan and bake the dish in the preheated oven at 180°C for about 20 minutes until the surface is golden brown.
Serve:

Garnish with fresh herbs such as basil or parsley and serve immediately.
Tips:
You can also add some spinach or other herbs to the filling to incorporate additional flavor and nutrients.
The filling can also be complemented with some tomato paste or a tomato sauce to add a bit of fruity freshness.
Enjoy your meal!