This recipe is adapted from Alton Brown.
This recipe works best with a microwave that has a rotating carousel inside.
Adding the vanilla to the powdered sugar before you add it to the butter-peanut butter mixture will save some time and simplify things.
For best results, vary the cooking time based on the strength of your microwave. This is not an exact science, as both the wattage and size of the microwave will affect the outcome. Use your best judgment based on your experience with your and other microwaves. I have a large, fairly strong microwave and I cut the cooking time down to 1:30 for the first cooking stage and 1:45 for the second stage.
- 8 ounces unsalted butter, plus more for greasing pan
- 1 1/4 cup crunchy peanut butter
- 1 teaspoon vanilla extract
- 1 pound powdered sugar
- 1/2 cup semisweet chocolate chips
Line an 8" x 8" baking dish with wax or parchment paper. Lightly grease with butter.
Combine the butter and peanut butter in a large glass, ceramic, or otherwise microwave-safe bowl and cover with plastic wrap. Microwave for 2 minutes on high. Remove from microwave and stir until smooth. Return to microwave and cook on high for 2 additional minutes. Remove from microwave.
Add the vanilla and powdered sugar to the peanut butter mixture and quickly stir to combine with a wooden spoon. Don't over beat the fudge. Just as the mixture starts to lose its sheen and becomes hard to stir, add half of the chocolate chips and as soon as they begin to marble the fudge, begin spreading the candy into the prepared pan, disturbing it as little as possible.
Sprinkle the remaining chocolate chips on top of the fudge and cover the top with a sheet of wax or parchment paper, lightly pressing down on the top of the fudge.
Refrigerate until completely cool, about 2 hours. Cut into bite size pieces and store in an airtight container at room temperature for up to a week.