Place the strawberries into a heat-resistant bowl. Sprinkle them with sugar and add the lemon juice. Microwave for 8 minutes.
Use cooking chopsticks etc. to lightly stir up the mixture and then microwave it for another 10 minutes.
Lightly stir the mixture again and microwave for 2 more minutes. Check on the thickness and microwave for another 2 minutes if necessary.
Use a spoon to remove any scum that forms and leave the jam as-is to cool.
Story Behind this Recipe
My friend told me that strawberry jam could easily be made in the microwave, so I tried making my own. It really was easy and delicious so I've made it repeatedly. It also comes out delicious when made with homegrown juneberries, raspberries, blueberries, etc., or even smaller amounts.
While it's heating up in the microwave, it will swell out quite a bit, so please use a somewhat large bowl. When removing from the microwave, the bowl will be hot so be careful. Even if it seems a bit watery, it will thicken as it cools. Adjust the cooking time and amount of sugar as needed. Don't cover the bowl with plastic wrap. If only making a small amount, use less time.