Squeeze the lemon juice into a small bowl, being sure to catch any pips. If you do not have a fresh lemon at hand, use two tablespoons of store-bought lemon juice (or 1 oz).

Use a small whisk to whisk in the mustard. Season with salt and pepper. Place the bowl onto a wet square of good-quality kitchen paper. This will prevent the bowl from moving as you whisk in the oil, as you need both hands for the next step!

Weigh out the oil in a small jug, then slowly drizzle the oil in the bowl, whisking continuously as the mixture emulsifies.

Drizzle over your favorite salads – or even cooked fish and vegetables. This batch will yield enough for a salad serving 4 people.