As others have said, adding DME is maybe not the best solution, but it is not difficult to do.
You could boil the DME for 10 minutes to solubilize it and achieve hot break, then chill to fermentor temperature and add to your carboy. No doubts about whether it will be sterile or if you would get odd off flavors from the DME.
I brewed 3 gal banana wine a while ago and it fermented out super thin (~1.004), so I made a 0.75-gal mini-brew of 2-row and oatmeal (60-min mash + 60 min boil) and added it to the fermentor. The fermentation kicked up again, yielding me a few alcohol points and the final gravity was around 1.015. No off flavors or any other sign that I didn't brew all the grain bill at once. Granted, the banana wine had little to no hopping, so I didn't have to worry about IBU to maltiness balance.