It sounds so sophisticated but it's really just the French version of cottage pie, as served in every neighbourhood bistro in Paris. Serve with green beans, Roman beans or a leafy green salad.
1kg red-skinned potatoes, peeled
2 tbsp olive oil
2 onions, finely chopped
750g minced beef
1 tbsp plain flour
400g tomato passato or sugo
Dash of Worcestershire sauce
1 tsp paprika
2 tsp thyme leaves plus thyme sprigs for serving
2 tbsp parsley, chopped
Sea salt and pepper
2 tbsp butter, chopped
150ml milk, heated
2 tbsp sour cream
3 tbsp grated gruyere or cheddar
3 tbsp grated parmesan
Roughly chop potatoes and cook in simmering salted water until tender, about 20 minutes.
Heat oil in a fry pan and cook onions over low heat until soft. Add beef and cook over medium heat for three minutes, separating meat with a fork.
Scatter flour on top and cook for another three minutes, stirring well, or until no longer pink.
Add tomato passato, Worcestershire sauce, paprika, thyme and parsley, taste for salt and pepper and cook for a further three minutes.
Tip beef into an oiled gratin pan.
Drain potatoes and mash, or push through a potato ricer. Beat in one tablespoon butter, hot milk, sour cream, two tablespoons each of grated gruyere and parmesan, salt and pepper and spread on top of beef.
Scatter with remaining cheese and dot with butter. Heat oven to 180C and bake for 20 minutes or until golden. Cut into squares and serve with fresh thyme.
Tip: To reheat, cut into individual squares and bake for 15 minutes at 180C.