How to use ajvar, the flavour-packed vegetable spread

• Adam Liaw's cevapcici rolls with ajvar and sour cream

A friend gave me a jar of ajvar. What is it, and how do I use it? L. Tobin

Ajvar is a delicious condiment made from minced, roasted capsicum and chilli, perhaps with added garlic or eggplants. It is sweet and slightly sour, smooth to slightly creamy, and vibrant red to vermillion, with a slightly smoky cooked capsicum aroma.

The cooked veg means it has loads of amino acids, so it's bursting with natural glutamic acid, which means umami. Packed into jars, it is generally made in the Balkan states and was originally a cheap substitute for caviar.

Salted fish roe was popular in Belgrade in modern Serbia until the late 1800s, when the delicious treat became scarce. Local chefs came up with this dish, which they nicknamed red caviar.

Spread ajvar liberally on crusty bread, alongside roasted or barbecued vegetables and meats, or blend it with yoghurt and olive oil to make a dip. It tastes so good that ajvar lovers eat it with a spoon straight from the jar.

Sometimes recipes tell you to add liquid and simmer for 10 minutes or until reduced by one third. It can take half an hour. What is the secret? D. Bond

Reducing is all about getting heat into the pan to create evaporation. By losing water, the liquid becomes thicker and more intensely flavoured.

You need a good heat source, a pan that conducts that heat well, and a wide enough surface area so the water can evaporate.

When you need to reduce liquid, have the heat on high until the liquid comes to the boil, and then reduce the heat until the liquid simmers. Do not cover.

Stir regularly so that whatever is in the pan does not catch. Watch and smell what is happening in the pan.

As to the time the author gives – here is a little secret. Some recipe writers are lazy and don't use a stopwatch when taking notes when they test recipes (if they test the recipes at all).

Sometimes they underestimate the time it takes to reduce the liquid and other times the underestimation is wild.

What exactly does "deglaze" mean? B. Devlin

An old chef once told me: "It is a sin to clean the bottom of a pan after cooking. You do it during cooking."

When protein and starch are heated together, as in a saucepan or frypan, they create new compounds in what is called the Maillard reaction.

That deep caramel-coloured layer on the base of the pan is packed with flavour. It is often essential to add a little more liquid, often wine, and then physically scrape this layer back into the food that is being cooked.

It adds more flavour to the dish and stops the food from catching. That process is called deglazing.

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