Wrinkly plums are great for this. Deseed the plums. The microwave I used has an output of 550 W and uses 1100 W energy.
De-seed the plums.
Add the plums and sugar into a bowl.
Heat them in the microwave for 5 minutes. They should turn out like this.
Give the plums a stir and they'll look like this. Then place them back in the microwave for a further 5 minutes.
Stir again. Then put them back in the microwave for 5 minutes once more.
They will look like this. By now most of the juice should have evapourated.
Once the plums have cooled, lay them out on a piece of parchment paper to cool.
It's up to you whether you dust them with an extra layer of sugar or not at the end.
Story Behind this Recipe
When I was little I used to go red-faced when I ate umeshu plums. They still get me drunk now! I used to help my mum making umeshu, and the flavour really reminds me of her cooking.
My microwave evapourates around 10 ml liquid per minute. Knowing this I was able to make some nice glacé plums.
You can use wrinkly or not-so-good-looking plums for this recipe. When heating the plums in the microwave the alcohol will evapourate off and you'll just be left with the delicious flavour, so they're suitable for people that don't drink alcohol. They look nice dusted with sugar at the end, but they might be a bit too sweet this way.