Sure. I put 3 oz of DME in each quart jar. I fill with warm water to an inch from the top. I wipe off the mouth and put a new canning lid on. I shake till there's none stuck to the bottom. I adjust the lid ring to finger tip tight. From there follow your pressure canner instructions. I process mine at 20 psi for 15 min.
I usually make this on a non brew day and can up a case or two.
Wort ends up about 1.035 which is great for building buddies. On the day I make my starter I sanitize my flask, stir bar, a funnel, and a chunk of foil. I put the yeast in and a couple quarts of premade wort. Bingo.
I actually do this even when I'm not planning on storing long term, minus the pressure part. I just process in a water bath. If you do it a night or two ahead of time it's perfectly safe to leave it on the counter or pop it in the fridge.
Or mash a couple extra pounds on the next AG brew and run off the last bits into quart jars and pressure can. If you are making a 1.050+ beer you probably don't even have to add any grain, just run an extra gallon of near boiling water through your grain after your last batch (or last runnings)