Since shipping cupcakes in a jar worked out so well, I decided to try it out with brownies to see how they would fare...I think they are actually better than the cake--everyone who tried them approved.
I started with brownie batter and added chopped up Reese's peanut butter cups (you can't go wrong with that combination. Ever). I baked them in the smaller mason jars at a lower temperature (325) because they were so thick. I ended up leaving them in the oven for almost 45 minutes--I just kept checking them until they were done since I had no idea how long to let them bake.
Anything in the jars does better with a ganache over the top, so Ben helped me make peanut butter ganache and pour it in over the brownies. We had a few after dinner and I froze the rest overnight. We shipped a bunch of them to Grandma for her birthday--success! I will definitely be making more of these.
Peanut Butter Ganache
*This recipe is for a thin ganache consistency--if I wanted to use it for filling or frosting a cake I would reduce the cream or increase the chocolate a bit
* 10 ounces milk chocolate, coarsely chopped
* 1/2 cup smooth peanut butter
* 1 cup heavy cream
* 1 teaspoon vanilla extract
To make the ganache, put the chocolate and peanut butter into a heatproof bowl and set it aside. Pour the vanilla extract and the cream into a saucepan over medium heat and bring it to a simmer. Pour the cream over the chocolate mixture, cover, and let it all sit until the chocolate is mostly melted--about two minutes. After that, stir the mixture until the everything is completely melted and smooth.