Fat rules. It makes food comforting, rich, balanced. Tender, crisp, caramelized, delicious. Watching Samin Nosrat’s exquisite series Salt Fat Acid Heat affirmed this long-held fixation of mine — fat is crucial to cooking.

I’m happiest when there are rivers of olive oil running through my food. A drizzle of earthy peanut oil, a toasty bead of sesame oil, a creamy spoonful of coconut oil. Dripping off sun-dried tomatoes, or the glossy coating on salad leaves. The way it pools invitingly in a jar of homemade nut butter, or emulsifies cooperatively in a cake batter.

And then there’s one of the best ways to wallow in the wonders of oil — confit. This traditional French process is a preservation method, where food is cooked submerged in fat very slowly and then stored, still submerged, until required. Although it’s generally associated with meat preservation, there’s no reason why you can’t apply the same idea to vegetables that you want to eat with relative immediacy.

It’s very easy — simply cover your vegetables in enough olive oil to completely immerse them, and place them in a low-temp oven for about an hour. The result is twofold: vegetables which taste as though they were cooked by the angels themselves, and the remaining, drained-off oil, now infused with whatever was cooking in it and ready to be funneled into a bottle for future use. I tried four different vegetable confits: cherry tomatoes, beetroot, parsnip and baby new potatoes, and each turned out amazing. The root vegetables became sweet and buttery — both in flavor and texture — the bland supermarket cherry tomatoes turned into jolts of sparkling intensity, and the potatoes, gently stewed in their own skins, were unbelievably creamy.

You are limited only by the season and your imagination — think confit leeks with juniper berries, confit butternut squashed into a risotto, or confit radishes with peppercorns. I recommend using a middle of the road olive oil — not an extra virgin, or anything too expensive. I grabbed the one which was on special this week at the supermarket, and it worked perfectly.

These recipes are really just suggestions, with quantities depending on the size of your vegetables and oven dishes, and the accompanying herbs, spices, and other flavors up to you. Each recipe yields only a fairly small amount, since I wanted this to be a starting point for the un-confit-confident, but you are welcome to multiply to suit your needs.

Despite the large quantities of oil used in the cooking, the vegetables aren’t weighed down. In fact, they are quite delicate, yet astonishingly luscious at a cellular level, and once you’ve cooked vegetables this way you’ll want to use them in everything.

Beetroot Thyme Confit

• 1 large beetroot, trimmed and peeled
• 1 tablespoon fresh thyme leaves
• Pinch salt
• 1–2 cups olive oil

1. Set your oven to 200°F and place a tray in the oven (to catch any drips).
2. Roughly chop the beetroot into chunks and place in an ovenproof dish — ideally one small enough for them to fit snugly, or large enough that they can be in one layer. Sprinkle with the thyme leaves and salt, and pour over the olive oil until the beetroot is just covered.
3. Place the dish in the oven and leave to cook for one hour, or until the beetroot is very tender when jabbed with a skewer. A couple of tiny simmering bubbles is fine as it cooks, but if it looks to be bubbling too hard, simply turn the oven down a little and leave it to cook for longer. Carefully remove from the oven.
4. To use immediately, remove the beetroot with a slotted spoon. Otherwise, transfer them with the oil to a clean, sterile jar and store in the refrigerator for up to a week. The oil will solidify in the fridge, so allow the jar to come to room temperature before using.

Cherry Tomato Confit with Lemon

• 1 cherry tomato punnet (8–9 ounces)
• Lemon zest, strips
• Pinch salt
• 1–2 cups olive oil

1. Set your oven to 200°F and place a tray in the oven (to catch any drips).
2. Place the tomatoes in an ovenproof dish — ideally one small enough for them to fit snugly, or large enough that they can be in one layer. Tuck the lemon zest in around them, sprinkle with the salt, and pour over the olive oil till the tomatoes are just covered. A couple might rise up and float, this is okay.
3. Place the dish in the oven and leave to cook for one hour. A couple of tiny simmering bubbles in the oil is fine as it cooks, but if it looks to be bubbling too hard, simply turn the oven down a little and leave it to cook for longer. Carefully remove from the oven.
4. To use immediately, remove the tomatoes with a slotted spoon. Otherwise, transfer them with the oil to a clean, sterile jar and store in the refrigerator for up to a week. The oil will solidify in the fridge, so allow the jar to come to room temperature before using.

New Potato Confit With Rosemary

• 1 pound small new potatoes, cleaned and dried but not peeled
• 1 tablespoon fresh rosemary leaves
• Pinch salt
• 1–2 cups olive oil

1. Set your oven to 200°F and place a tray in the oven (to catch any drips).
2. Place the potatoes in an ovenproof dish — ideally one small enough for them to fit snugly, or large enough that they can be in one layer. Sprinkle with the rosemary and salt, and pour over the olive oil till the potatoes are just covered.
3. Place the dish in the oven and leave to cook for one hour, or until the potatoes are very tender when jabbed with a skewer. A couple of tiny simmering bubbles in the oil is fine as it cooks, but if it looks to be bubbling too hard, simply turn the oven down a little and leave it to cook for longer. Carefully remove from the oven.
4. To use immediately, remove the potatoes with a slotted spoon. Otherwise, transfer to a clean, sterile jar and store in the refrigerator for up to a week. The oil will solidify in the fridge, so allow the jar to come to room temperature before using.

Parsnip Thyme Confit

• 2 medium-sized parsnips, trimmed
• 1 tablespoon fresh thyme leaves
• Pinch salt
• 1–2 cups olive oil

1. Set your oven to 200°F and place a tray in the oven (to catch any drips).
2. Slice the parsnip into sticks and place in an ovenproof dish — ideally one small enough for your vegetables to fit snugly, or large enough that they can be in one layer. Sprinkle with the thyme leaves and salt, and pour over the olive oil till the parsnips are just covered.
3. Place the dish in the oven and leave to cook for one hour. A couple of tiny simmering bubbles in the oil is fine as it cooks, but if it looks to be bubbling too hard, simply turn the oven down a little and leave it to cook for longer. Carefully remove from the oven.
4. To use immediately, remove the parsnip with a slotted spoon. Otherwise, transfer to a clean, sterile jar and store in the refrigerator for up to a week. The oil will solidify in the fridge, so allow the jar to come to room temperature before using.

Note:

If you are planning on using garlic either as the star or a flavor addition, the confit must be either consumed immediately or cooled as quickly as possible and then stored carefully in a clean, sealed jar in the fridge. Unfortunately, garlic has a high risk of botulism when stored in oil and left at room temperature.