How to get crunchy potatoes and crispy pork crackling. By Matt Preston.

We answer your big kitchen questions.

Oliver Ford

It's perhaps not surprising the kitchen questions you wanted answered often revolve around getting the perfect texture, whether the perfect golden crackle, the ideal crunchy potatoes or couscous that's as fluffy as a cumulus nimbus cloud.

1. Why do my biscuits spread out and blur together when I bake them?

The blame usually lies with your butter being too soft when you incorporated it into your biscuit mix. Remember that with room temperature butter your finger should be able to dent it but not push its way all the way through. If you've forgotten to leave your butter out of the fridge don't use the microwave; far better to cut the cold butter into cubes and leave out to soften for 15 minutes.
The other reason the biscuits might blur together is that you just tried to cram too many biscuits on one baking sheet. Remember, biscuits need space.

2. Are baking powder and baking soda interchangeable?

No, they aren't. Baking soda needs added acidity in some form to activate it. Baking powder contains cream of tartar and it is the acidity this brings that leavens cakes and batters. Use baking soda instead of baking powder and you'll end up with dense, unrisen cake.

3. My stir fry isn't crispy?

The magic of wok cooking - or so my Chinese friends tell me - is the "breath of the wok". That is, the intense and almost instant heat that a properly seasoned wok has when placed over a roaring flame.
The most common problems with wok cookery are overcrowding the pan so this heat dissipates, using too much liquid, which stews the ingredients, and not being properly prepared so things cook unevenly. So chop everything to the required size before you start using the wok, get the wok hot before adding anything, add your ingredients in small batches with the hardest, most dense ingredients (which will take the most time) first, and remove one batch before adding the next if making a big stir-fry so you don't overcrowd the pan. Then you should never be faced with the horror of serving a soggy stir-fry again.

4. How do you get perfect pork crackling?

Dry, well-scored skin that's well-greased and a very hot oven are the secrets to great crackling. To ensure a dry skin get your butcher (or use a razorsharp craft knife) to score the skin and fat. Dry the joint with paper towel and then rub salt into the surface and scored crevices of your pork skin.
Leave overnight in the fridge for the salt to draw out some of the moisture from the skin. When you need to cook the roast, bring it back to room temperature, brush off all the salt, dry the joint with kitchen towel and finally massage the joint well with oil and something acidic like vinegar or lemon juice. Place the joint on a wire rack or trivet in a roasting pan and place in a searingly hot oven (230C) for 30 minutes to give the crackling a head start before turning down the heat to finish it off with a low slow cook of a few hours. Elevating the meat this way allows the heat to circulate easily and freely all around it.

5. How do I get my roast potatoes crunchy?

First off, pick the right potatoes. You want medium to higher starch levels, such as coliban, pontiacs or sebago and not waxy ones like kipflers or pink firs. Peel and cut the potatoes into three-bite size chunks. Place in a pan covered with cold water. Bring to the boil and then simmer for five minutes or so. You don't want to cook the potatoes, just parboil them to soften them ever so slightly at the edges. Drain them, return them to the hot pan (but off the heat) and then let them steam off a bit to remove moisture from their surfaces.
Next place a lid on the pan and shake the potatoes vigorously so as to fluff up the edges a bit as they knock around the enclosed pan. Remove the lid and let more steam blow off and dry out the potatoes a little more.
While this is all happening, place a low-sided roasting tray containing a good glug of oil into a 180C fan-forced oven. When the oil is hot, carefully place the roughed-up potatoes into the pan. Spoon some of the excess oil in the pan over the exposed faces of the potatoes and return to the oven.
Roast for 70 minutes but turn the potatoes over after 40 minutes, or when their bases are golden and crispy. Remember that making great roast potatoes is actually about a two-hour process, so leave yourself plenty of time to get them really crunchy. Roast potato problems usually come from trying to make them too quickly.

6. My couscous always sticks - Help!

Overcooking, stirring, and not fluffing up the cooked couscous are the most common problems with couscous cookery. Couscous is effectively already cooked and so it just needs to absorb some moisture to soften the little pasta grains. While the easiest way to do this is to pour a cup of boiling water or boiling stock over a cup of couscous and cover for five minutes for the couscous to absorb the liquid, when making a larger batch of couscous use a large baking dish. This helps the couscous expand without the pressure and weight of too many grains above it as would happen in a bowl. Warm the baking dish first then spread out three cups of couscous over the bottom. Pour over 4 1/2 cups of very hot stock (or boiling water) and leave it uncovered for 15 minutes. In both cases at the end of the allotted time drizzle on some olive oil and fluff up the plumped couscous with a fork.