Place a large saucepan over high heat.

Add the olive oil, garlic, oregano, onion and celery and saute for 5 minutes, until the onion is starting to become translucent.

Add the salt and ground beef, stirring continuously to break apart the meat while it browns.

When the beef is browned add the tomato paste and stir well.

Add the beef stock and red wine vinegar and simmer uncovered for 20 minutes until the liquid has reduced.

Add the thyme and green beans and simmer for 5 minutes before removing from the heat.

Spoon the beef mixture into your casserole dish and set aside.

Preheat your oven to 175C/350F.

Fill a large saucepan two-thirds full of water and bring to the boil.

Add the cauliflower and cook for 7-10 minutes until tender.

Carefully pour the water and cauliflower into a colander and drain well.

Return the drained cauliflower to the saucepan, along with the butter, salt and pepper.

Using your stick blender, blend the cauliflower into a smooth mash.

Add the egg yolks and blend well.

Gently spoon the mashed cauliflower onto the beef mixture in your casserole dish.

Sprinkle with paprika and oregano.

Bake the pie in the oven for 25-30 minutes, until the mash is golden brown.

Serve immediately or chill and store in the fridge for up to 1 week.