It’s what I do.
I make as much as possible can fit in my available mason jars. I simply boil some dme and water for about 10 minutes then pour it into the jars while it’s boiling hot. Then I put the kids on and flip them upside down to sterilize the whole jar.
Then I place the jars in my pot in case one breaks while they cool. When they are cooked I store them in the fridge. And starters take 5 minutes to make.
A few things to keep in mind,
Wear good gloves. Those jars get pretty warm
When you pour the wort into jars do it in a sink, and eye protection is probably a good idea. (Thermal shock can break glass)
It’s not the “safest” way but it works and I’ve had jars in the fridge for 6 months with no issues