Why in the world take up freezer space with all that liquid? Just as with the bullion cubes or granules, the trick is to get the flavor into the smallest volume possible for storage. You can always add hot water!

I used to do something like this when I had a big garden and odds and ends of excess that didn't lend itself to regular canning or drying. I would quickly blanch the vegetables, then puree them. The puree was put into ice cube trays and frozen, then put into heavy freezer bags for storage. If I had enough of it, I'd put up some pint or half pint jars with salt and citric acid to preserve it (water bath canning). Or you could pressure can it, but that just cooks the life out of it. I actually made a "veggie leather" with it too. The boys used to eat a lot of this made with squash, carrots, apples and assorted other things. I've got a recipe around here somewhere...

But why put onions or garlic into it, unless they might otherwise go bad? Use those things fresh if at all possible! And I simply can't imagine using either potatoes or cabbage family vegetables at all for this. Again, they are best fresh. Broccoli, etc. is best frozen by itself and added as needed.

But, of course, each to his/her own. :)