Grape jam has a nice balance of tartness and sweetness, which compliments the creaminess of peanut butter well, making it a great choice for this recipe. If you don’t have grape jam, you could use strawberry jam, cherry jam, raspberry jam, or literally any other kind of jam you prefer.  In fact, if you have a little extra time, you can also whip up a quick homemade jam or berry compote on your own.