Mongo, the reason you don't just toss weed in is mainly for two reasons.
One, being the fact that tossing it in, you're more likely to burn it. When you simmer it, the oil absorbs the THC completely, which is why consuming cannabis is a much longer lasting and more powerful experience. When you smoke you don't get all the THC, most of it gets burnt, some of the smoke doesn't get into your lungs (i.e. when a bowl is cherried after you finsh smoking), and unless you hold in the smoke for the entire 10-15 seconds, deep in your lungs, you're not gonna get all the THC. Just dumping the weed into the brownie mix is inefficient.
Two, who wants to chew burnt chucks of leaves and weed in your delicious chocolate brownies.
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Back on topic,
I've made the famous applesoft recipe many times, and every time it has knocked me off my socks. Off the ground. Off this earth. I don't know if it's been posted yet but just check out
http://applesoft.com/brownies/
It's not always up (the website) but you can easily just use Google cache. I added a bit of flair to it though:
Space Cake... MMM!!
Basically... pot brownies, or whatever sweet edible cannabis product you may want to use. Cake, brownies, cupcakes, that kinda stuff. And then take about 1/4 of shrooms or more, grind em up into almost a powder, take some frosting, or Nutella in my case, put the frosting (ONLY the frosting) in the microwave for 15-30 seconds to make a bit easier to... MIX the shroom powder in. Mix it good, make sure to get every single grain of shroom into it, mix and mix and mix, so everyone gets a good even ammount. Spread it onto the brownies, cake, cupcakes, what-have-you.
Then consume.
Take a trip.
Enjoy.