To make strawberry jam in a microwave, you will need:
- 500g fresh strawberries
- 500g white sugar
- 50ml freshly squeezed lemon juice
- A single heaped tablespoon of unsalted butter
- Fresh green herbs for garnish
Clean the strawberries by removing the stems and leaves. Squeeze the lemons to produce the volume of juice required. Place the strawberries and the lemon juice in a microwave-proof bowl. Set the microwave to maximum power and nuke the fruit for as long as it takes for it to become soft. Inspect the work in progress from time to time, since microwave ovens vary considerably in output. This requires that you exercise vigilance and good judgment. Stir three or four times during this process.
Remove the hot strawberry and lemon mixture from the microwave and reduce the softened fruit to a pulp. Pour in the white sugar and stir. Set the microwave to low power for the next stage. Return the bowl to the oven for a quarter hour or so. Maintain the vigilance and good judgment already referred to by inspecting the contents from time to time, as the sugar goes into solution.
Now for the drama and high heat. Return the microwave setting to maximum for about 20 minutes or so. Note that the sole nightmare of microwave jam is the capacity of the liquid mass to suddenly froth and boil, trying its damndest to climb out of the bowl and smear itself all over the interior of the oven. Regular stirring and inspection prevent this hazard.
Check that the jam has set, like this: pour a tablespoon of the jam-in-progress onto a clean saucer that has been thoroughly chilled in the fridge. Shove a clean finger through the stuff and if it wrinkles, the jam is ready to go. If not, more heat, and repeat, until wrinkles arrives.
Remove from the microwave and stir in the unsalted butter. Allow the mass to cool a little, as you sterilise the containers. Do this by boiling the bottles and their lids for a few minutes. This is essential to kill off all microscopic life forms and so ensure an adequate shelf life for the unopened jars of jam.
An alternative to boiling is to use the dry heat of the convection oven set to 110°C. Don’t forget the bottle tops. Pour the jam into the sterilised jars, fit the sterilised lids and leave them to cool. Label the jars and store them safely for later consumption.