This article is part of Reason's special Burn After Reading issue, where we offer how-tos, personal stories, and guides for all kinds of activities that can and do happen at the borders of legally permissible behavior.
The hardest part about making pot brownies is the math. When you're sitting in your kitchen looking at a jar of bud, a box of butter, and a block of chocolate, the whole project can seem daunting. Fear not: Basic arithmetic and baking skills are all you need to produce your very own edibles.
First, figure out your recipe yield. I make a recipe that produces 28 brownies. Let's say I want each brownie to have 10 mg of THC—the standard dose according to the state of Colorado. Unless you have specific information from your supplier or cause to suspect otherwise, a reasonable assumption is that your bud is about 10 percent THC. (You can determine this more scientifically by buying cheap testing tools online.) 10 mg x 10 x 28 = 2,800 mg, or about 3 grams. My preferred recipe calls for three-fourths of a cup of butter. Which means I should combine one and a half sticks (three-fourths of a cup) of butter with my 3 grams (a little less than an eighth of an ounce) of weed.
But you want to get as much of that THC as possible from the plant material into the butter. After a semi-scientific exploration of various techniques, here's my recommendation, inspired by the work of cannabinoid scientist Tamar Wise as described in High Times.
You'll need to toast your cannabis. The fancy term for this is decarboxylation, which converts THCa into THC, the stuff that gets you high. Grind up your pot. If you don't have a dedicated grinder, you can throw it into a small food processor, or just break it apart with your fingers until it is roughly the texture of coarse sand. Spread it on a baking sheet and pop it in a 240-degree oven for an hour. Shake the pan a couple of times during that period to prevent burning. Wise recommends lightly spraying the toasted weed with Everclear when it comes out of the oven to break down the cellulose and maximize the release of THC, but this step is optional.
Next, infuse the butter. You can do this in a slow cooker set to low or in a small, heavy-bottomed saucepan on a burner on the lowest available setting. Combine your ground cannabis and your butter, then let the mixture cook over very low heat for a long time—at least three hours, but a full six hours is better. Stir occasionally. Strain the resulting mixture through cheesecloth, squeezing the excess butter from the spent greens.
I live in D.C., where this is a legal activity, but note that your house will smell very distinctively of marijuana during this process, so don't imagine you can do it stealthily.
If you have gone to all the trouble to produce your own cannabis butter, I strongly urge you not to waste it by throwing it into a boxed mix. Especially not when the best brownie recipe of all time is so easy: Baker's One-Bowl Brownies lend themselves particularly nicely to this preparation, since the recipe begins with warm melted butter, which is exactly what you will have once you are done.
Simply add 4 ounces of chopped unsweetened baking chocolate to your three-fourths of a cup of hot cannabutter and stir until the chocolate is melted. If the butter isn't hot enough to melt all of the chocolate, pop it in the microwave for 30-second intervals until combined. Then add 2 cups of sugar, 3 eggs, and 2 teaspoons of vanilla. Stir to combine, then add 1 cup of flour and stir again. Pour the batter into a foil-lined and greased 13×9 pan and bake for 30 minutes at 350 degrees. The brownies should be just barely set in the middle when you take them out. They will firm up as they cool. Cut the resulting batch into 28 brownies.
A word on dosing: Pot infusions are an inexact science, and everyone reacts to marijuana differently. Consider starting with half a brownie; 5 mg is the generally accepted "rookie" dose for edibles. You can achieve the same effect by simply replacing half the cannabutter with regular butter.