Potato Dauphinoise and caramelised onion pie

Potato gratin in a pie.
Potato gratin in a pie. Photo: Katrina Meynink
Dietary
Vegetarian

An assault on all the senses, this is the ultimate in comfort and in pie. I love how blatantly hedonistic this is. It takes no prisoners, and why should it? It is a true celebration of creamy, cheesy potatoey goodness. I would serve this with a bitter green salad for cut-through and a hefty glass of red. Preferably in front of a fire. With absolutely nowhere else to be.

Ingredients

445g sheet shortcrust pastry (I used Careme)

600g small potatoes (I used new potatoes and left the skin on)

1 tbsp olive oil

1 tbsp butter

1 large brown onion, finely sliced

3 garlic cloves, finely sliced

1 tbsp rosemary leaves, finely chopped (plus extra leaves to scatter)

1 cup thickened cream

½ cup full cream milk

1 tsp salt

¼ cup finely grated parmesan plus 2 tbsp for serving

¼ cup finely grated gruyere

¼ cup finely grated comte

250g caramelised onion jam (store-bought or use my recipe)

2 tbsp melted butter

Method

1. Preheat oven to 170C fan forced (190C conventional).

2. Thoroughly grease a 25cm round loose-bottomed pie tin with butter and line the base with baking paper. Drape the pastry over and into the pie tin and trim the excess. Allow to rest in the fridge for at least 15 minutes.

3. Blind bake the base, using baking paper and baking weights or rice, for 10 minutes or until lightly golden. Remove the weights and paper and cook until a deep golden colour (about 10 minutes). It's important to cook the base all the way through so you have a firm base before you fill it with creamy potatoes.

4. Slice your potatoes into rounds using a mandolin, you want them as thin as possible to ensure they cook in time and also to help release their starch which will thicken your cream sauce.

5. Place a frypan over medium heat. Add the oil and butter, and once foaming, add the sliced onion and cook for 5 minutes or until soft and translucent. Add the garlic and rosemary and cook for an additional minute, before adding the cream, milk and salt.

6. Turn the heat to low and add most of the potato rounds, reserving about 100g of them for the topping, and cook for about 15 minutes. Keep a relatively close eye on this, you don't want the cream to burn or the potatoes to cook so quickly that they become too soft and lose their disc shape. Give the frying pan a regular shake, every 5 minutes, to move the potatoes through the cream.

7. Add the quarter-cup of parmesan, and the gruyere and comte, turning the potatoes gently to coat. Once the cheese has melted, check that the mixture has thickened significantly and is just coating the potatoes. It should coat the back of a spoon quite thickly. If it still seems runny, cook a little longer. 

8. Gently scoop your potatoes into the pastry lined pie dish. It doesn't need to be exact layers but try and keep the filling quite level until it almost reaches the top of the tin. Smear the onion jam across the top of the potatoes.

9. Toss the reserved potato slices in the melted butter then place these, slightly overlapping each other, over the top of the pie (they will shrink a little as they cook). Sprinkle over the remaining 2 tablespoons of parmesan and bake for 40 minutes. If the potatoes on top are taking on too much colour, gently cover with foil, then remove the foil for the last 5 minutes of cooking time, to allow the top to crisp.

10. Remove from oven and allow to cool to a warm temperature before cutting – if you cut this pie while very hot, the filling tends to go everywhere. Scatter with the extra rosemary and serve.