Make the brownies according to box directions. Let cool completely, then cut into cubes.
Beat the pint of heavy cream until soft peaks form, then add in powdered sugar to taste. I usually use about 1/4 c. or so. Set aside.
In a glass bowl, add the chocolate chips and 2/3 c. heavy cream, then microwave them until the chips are just melted. Stir until shiny and smooth.
Rinse and dry the raspberries.
In each mason jar, layer the components like this: cubed brownies, chocolate ganache, whipped cream, and raspberries, then repeat once more, so raspberries are on top. Drizzle a little extra ganache over the raspberries.
Makes approx. 4-6 jars, depending on how much cream and ganache you use. You can always make a little more of those two things if you want to, so you can use a little more if you like!