Put a couple of side plates in the fridge to chill as you prep the jam.

Finely chop your strawberries with a knife or pulse in a food processor until you have a mulch of fruit before you. Scrape into a preserving pan or the largest saucepan or casserole you have and stir in the sugar.

Scrape the seeds out of the vanilla bean and add them plus the whole pod to the pan along with the zest and juice of the limes.

Once the sugar has dissolved (give it a good stir to help it all amalgamate) turn the heat up to high and bring the pan of fruit to a rolling boil. Do not leave it's side. Stir frequently to ensure none sticks and burns on the bottom of the pan.

Keep at the rolling boil stage, adjusting the temperature of your hob as needed. Keep on stirring and what you are looking for is the fruit to evaporate off enough liquid that the mixture becomes heavy on your spoon - usually about 10 minutes in. Look for "flakes" forming i.e. when you lift your spatula out, the jam will fall off in flakes back into the pan, rather than a steady liquid stream. Another good test is to take the jam off the heat, place a teaspoonful onto a cold plate and leave for a few minutes then push your finger through it - if it ripples and wrinkles, mostly holding this shape, then it is ready. A final test is to take the temperature of the jam and if it reaches 105°C it is ready. I find this the least reliable method and do not use it any more but it is in all the jam making books I've read!

Once the setting point has been achieved, retrieve and discard the vanilla bean then ladle your jam into sterilised* jars and seal immediately. Leave to cool completely before using.

Note - if the jam is runnier than you would like once completely cold, simply return it all to the washed out pan and boil again and you should be just fine.