Whether you have leftover roasted potatoes or you just wanted to prep them in advance, let the potatoes cool to room temperature and transfer them to a shallow airtight container or resealable plastic bag. Then, pop the potatoes into the fridge within 2 hours of removing them from the oven.
Preheat the fat. While the potatoes parboil, add the oil or butter to the roasting pan, transfer it to the warm oven, and heat it for about 5 minutes before adding the potatoes. This allows the outside of the potatoes to crisp up nicely and not just absorb the cold fat when you put them in the oven.
If you know you are going to be pushed on Christmas Day, then it is possible to half-roast the potatoes the day before (see Preparing Ahead, below). On Christmas Day the potatoes just need to be re-roasted in a hot oven for about 20 minutes. Preheat the oven to 220C/fan 200C/gas 7.
If you want to get ahead, why not boil them in advance, then toss in a little oil and store in the fridge until you're ready to roast them. There's no need to bring them back up to room temperature, just toss them into hot fat straight from the fridge.
Heat your oven to 400 degrees, spread potatoes on a sheet pan and cover them in tin foil. Re-roast them until they're warm all the way through, about 10-15 minutes. Remove the cover for another five to add crispiness. 6.
The day before (WITH part-baking)
Cover and place in the fridge overnight. To finish them off the following day, heat more oil in a tray and cook for about 15-30 minutes until golden and crispy (should be closer to 15 but sometimes this can take a while as the potatoes will be cold from the fridge).
The Jewish Week Food & Wine recommends using your oven to resurrect your fried food, since it's the easiest method with the crispiest results. Preheat a large baking sheet (with or without a wire rack) in your oven at 400 degrees Fahrenheit. Once it's hot, spread out the leftovers in a single layer.
Toss the potatoes in the fat (you could get the potatoes up to this stage the day before, simply cover them with clingfilm or tin foil and pop in the fridge or in a cool place until needed), then roast for 30 minutes, or until lightly golden and three quarters cooked.
As if better flavors and saved time were not enough to convince you to parboil, you can even prep your potatoes early this way. Parboiled potatoes are good for up to one to two days after you remove them from boiling.
Give them a cold water bath: Once your potatoes are chopped, toss them into a large bowl. Then cover the potatoes completely with cold water and let them soak for at least 30 minutes (or up to overnight). This will help to rinse off the excess starch and help the potatoes crisp up beautifully in the oven.
To make crispy roast potatoes, the temperature of the oven needs to be hot 220°C or 425°F - but if the oven is too hot the potatoes will burn before they crisp up. If the oven temperature is too cold your potatoes will not be crispy.
To parboil your potatoes to perfection, cut them into large chunks and put them in a pot of boiling water for around ten minutes, depending on the size. Once the outside is soft but the inside still raw and firm, you're ready to roast!
The short answer is yes.
You can absolutely peel potatoes ahead of time.
If you cook potatoes in water, it's likely they will become mushy after a while. To fix this and keep your potatoes intact, pour a little bit of vinegar (white, wine or cider) in cooking water. It works like magic! Don't forget to rinse your potatoes afterward.
To ensure a crispy outside and a fluffy inside to your potatoes, Gordon advised: “Shaking up the edges, coating in semolina and getting the fat really hot first all help ensure crispy, golden outsides while the middles remain fluffy.”
Roasted potatoes can become soggy if the water content in the potato isn't fully cooked. Different potatoes have different water content percentages. Also, be mindful of the oil. Potatoes can react like sponges; too much oil can make your potatoes appear to be soggy.
Do cooked potatoes go brown? No. Once the starch is cooked, the potato won't go brown even if it is exposed to air for a while. If you have lots of potatoes that need to be used up, the best option is to peel and cube them, then cook them and freeze them in portions.
Add lemon juice or vinegar
Lowering the pH of the potato helps fight off oxidation. Just like you might use a squirt of lime juice to keep guacamole from browning, a bit of lemon juice or white vinegar in the bowl with the potatoes will ward off gray hues.
Q: After boiling potatoes, how can I keep them from turning brown overnight so I can make potato salad the next day? A: Place the potatoes in water to cover and add some acidity like a teaspoon of concentrated lemon juice or white wine vinegar to keep from browning.
Soak the potatoes in cold water to remove the excess starch from the outside of the potato. There are a few reasons why you want to remove that starch (it makes the potatoes burn, it keeps them from crisping up, it turns to sugar) but all you really need to remember is to soak them at least one hour.
Parboil them in a pan of boiling salted water for 15 minutes – this will ensure that the insides become really fluffy. 2. Drain in a colander and leave to steam dry for 2 minutes – this will help the fat to stick to the potatoes.
COOLING AFTER PARBOILING
When the potatoes are roasted from cold they will have set and stopped cooking, and excess moisture from the boiling process will have evaporated. So when cooked in hot fat the outside will have a headstart and become perfectly crisp while maintaining that delicious fluffiness inside.
If you must store fried foods in the fridge, cool them completely, then store in an airtight container with a paper towel to absorb moisture. The food will last three to five days that way. This may be the most crucial step for the crispest results possible.