Using your hand mixer or stand mixer fitted with the paddle attachment, beat the softened, room temperature cream cheese on medium-high speed for about 4-5 minutes or until it's light and very smooth.This will help eliminate any lumps later.
Add in the light brown sugar, creamy peanut butter, and vanilla and continue to mix together on medium-high speed until blended.
Reduce the mixer to a slower speed, adding in the heavy whipping cream and slightly whisked eggs, mixing together until just combined. Do not over mix the cheesecake batter.
Fold in the chopped Reese's Miniature Peanut Butter Cups using a spatula.
Pour the cheesecake mixture into the cooled crust. Don't forget to have the springform pan wrapped in foil before the next step! Top with any extra pieces of Reese's peanut butter cups, if desired.
Using a large microwave safe glass measuring cup, boil close to 4 cups of water in the microwave.
Place the cheesecake into a roasting pan, then place onto the middle rack of the oven. Before closing the door, carefully fill the roasting pan with boiling water until it reaches halfway up the sides of the springform pan. Bake the cheesecake for approximately 55-60 minutes at 325ºF. When done, turn off the oven and, keeping the door closed, allow the cheesecake to cool in the water bath for 45 minutes.
Carefully remove the cheesecake from the roasting pan, placing it on a trivet or wire cooling rack to sit at room temperature for 45 minutes to an hour.
Once cooled, remove the aluminum foil layers, then loosely cover the top of the cheesecake with aluminum foil or plastic wrap and place in the refrigerator for a minimum of 4 hours or, my preference, overnight.
When ready to serve, release the sides from the pan, slice, and enjoy!