I found this recipe on Bluesky one sleepless night from a rather unlikely source (he usually posts political stuff) and it sounded so good I wanted to give it a go. He also linked to a recipe, which I used as a base but ended up changing it a bit (as usual). For example, I left out the heavy cream and used a salted butter & olive oil mix to caramalise the onions, plus swapped out gruyere for manchego (finely grated so it stirs in and melts easily). And only stirring after mashing so the potatoes didn’t get all gluey.
Anyhow, the basic idea is gorgeous mashed potatoes with caramalised onions and cheese stirred in, so it’s pretty flexible. I’ve also made this with a mix of sweet onions and shallots and then stirred in wilted baby spinach at the end – also delicious.
Ingredients & instructions below…
- 3 tbsp salted butter
- 3 tbsp olive oil
- 3-4 sweet onions (depending on size), halved and thinly sliced
- 1 kilo potatoes, washed and peeled
- 70 gr salted butter, room temp
- 100-150 gr manchego cheese, finely grated
- freshly ground black pepper
- salt to taste
Heat the butter and olive oil in a skillet on medium-low heat. Add the onions and cook for about 10 minutes, stirring often, so the onions begin to cook down. Reduce the heat to low and continue cooking, stirring occasionally (about every 10 minutes) until your desired caramelisation is reached. This usually takes me about 45-60 minutes. Set aside.
While the onions are caramalising, wash, peel and chop the potatoes. Slice into halves and then into same-size chunks (not too small). Cover with cold water in a large pot, season with a pinch of salt. Once the onions are done bring the potatoes to a boil and cook until they are fork tender, about 12-15 minutes. Drain well and put them back in the pot.
Mash the potatoes (with a masher or ricer) until they are the consistency you like. Stir in the butter and mix well (using masher or wooden spoon), then gradually stir in the grated cheese until everything is nicely blended and the cheese has melted. Season as you like after each addition. Add about 1/2 – 3/4 of the caramalised onions and stir them in. Serve with the remaining onions on top.
Caramelising onions and shallots together also works well and, if you like, stir in some chopped wilted baby spinach at the end “for health”. Here I have topped them with grilled chistorras (to undo the health thing).