Add about 1 cup ot broth to the pan, put the pan back on the burner, and as the broth is boiling down scrape against the crust with a wooden spoon to dissolve it. Repeat this process as needed until only 1 cup or so of broth remains. Use this remaining cup to deglaze for the final time. Scrape the pan of broth over the heat just long enough to dissolve the crust. (Don't simmer for more than a minute or two, or the jus will lose vitality and end up tasting like concentrated broth.) Strain through a fine-mesh sieve to remove the caramelized vegetables and bits, cool, and store in an airtight container in the refrigerator until ready to use.