Add grains to 6 qts 150 F water to stabilize at 130 F or so for 30 minutes.
Add 3 qts boiling water to stabilize at 155 F for 60 minutes.
Heat or add boiling water to stabilize at 168 F for ten minutes.
Sparge with about 2 gallons 170 F water to boil volume.
Add ingredients at time listed. Chill. Pitch yeast.
The addition of vanilla in this recipe is tricky. I added about 4 tbsp to primary and at bottling time there was no vanilla aroma or taste whatsoever. I added vanilla extract to taste, testing first on a small sample and multiplying to find the amount needed for the full batch. About one tbsp gave me a strong vanilla flavor that still allowed the chocolate and roast to shine through. You will find that adding the vanilla actually makes it taste more chocolatey.
I found this took a while to carbonate properly but once it did, it was a treat. I use DME to carb which works kind of slowly. If you want quicker results, I suggest corn sugar. This is a very nice for a relatively high gravity brew when fresh. The vanilla seems to cover up off-notes from lack of aging. Of course, as it ages the vanilla flavor wanes as well, revealing a wonderful new complexity.
I should also note that it certainly didn’t taste like 83 IBU’s. I get a rather weak boil on my stove so imagine the effeciency of bitterness extraction from my hops is a bit low. You might want to reduce the amount a small amount to compensate. I should add that magnum hops are wonderful and smooth-tasting in stouts and porters even at high bittering levels so that’s probably a big part in the perceived low bitterness.