All you need to do is combine the ingredients and microwave them. Here's an easy recipe for sweet and salty, glistening mitarashi dango sauce, just like from a shop.
When I made dango, I decided to try and also make my husband's favourite sauce for mitarashi dango. It turned out really well so I wrote down the recipe and uploaded it here.
The length of time in the microwave varies according to the make and type of machine. It should be bubbling after Step 1, and thickened after Step 2.
Enjoy Japanese food around the world.