First, choose your lemons. They should be heavy for their size, and fully ripe with no tinges of green - these are the juicy ones.

Scrub them well. Finely grate the zest of one lemon into a mixing bowl, add 150g caster sugar and stir well for a few minutes to release the zest's aromatic oils.

Squeeze enough lemons (about four to five) to get 250ml of juice, pour it in and stir until the sugar dissolves. Add 450ml chilled still or sparkling water, and serve over ice.

As lemons can vary quite a bit in acidity, change the proportions of water and sugar to suit your taste.

Now, here's where the fun begins - use this base as a blank canvas on which to build delicious variations.

For example, you can substitute half the water with ginger ale, brewed tea such as Earl Grey, rosehip or lemongrass, or fresh fruit juices like pineapple, grapefruit, watermelon, peach or pear.

Chunks of any of these fruits will transform lemonade into a party punch.

For a rosy-pink lemonade with a lovely flavour, use lightly sparkling water and stir in a large handful of halved, pitted fresh red cherries. Try raspberries and blackberries too.

You can even add herbs. Mint, lime leaves and all kinds of basil suit lemonade well: Stir them with the sugar to extract their essences.

And of course, for adults-only picnics, consider spiking your lemonade with compatible liquors and mixers, such as citrus vodka, gin, limoncello, Campari and so on.