Two Gatsbys

Strike grains with 3.47 gal of water at 162.8 °F.
Mash at 151 °F for 60 min.
Vorlauf and lauter 2.02 gal in your first runnings.
Add 3.48 gal of sparge water at 168 °F.
Vorlauf and lauter 3.48 gal in your second runnings.
Your combined runnings should be 5.5 gal.

The much-vaunted Westvleteren 12 has been an object of desire for a good many brewers and beer lovers. Rumors abound that the recipe for the beer is blindingly simple. The fermentables are supposedly just Pilsner malt and Belgian candi syrup, a byproduct of the sugar making process that wasn’t available to US brewers until recently. Now several folks import the stuff from Belgium, and some are even making it here in the States, so take this as an opportunity to explore their different properties.
For 5.5 gallons at 1.096, 32 IBUs, 3.8 SRM, 9.3% ABV, 90-minute boil
GRAIN BILL
19 lbs
Dingeman Pilsner Malt
1.5 lbs
Belgian candi syrup (D2 or D-180)
MASH SCHEDULE
Rest
151°F
60 minutes
HOPS
0.75 oz
Magnum
Pellet
11.6% AA
60 minutes
YEAST
WLP530 Abbey Ale or WY3787 Trappist High Gravity
NOTES
Add the syrup late to the boil, with 10–15 minutes remaining. It will allow for better hop utilization. Alternately you can add the syrup to the ferment as opposed to the boil. You’ll need a large amount of yeast, so consider making a starter beer. (In fact, try the variant below.) And for the love of all that’s holy, pitch and start this beer in the low 60°sF and let it rise to fermentation in the higher 60°sF. A beer with this much oomph is asking for fusel alcohols and headaches if you let it ferment hotter.
VARIANT
The Singular Half: Cut all the ingredients in half and ferment away for a not-quite Single or Double. The yeast can be used to ferment the Quad.