Preheat the oven to 350°F. Grease and flour an 8- or 9-inch cake pan.

In large mixing bowl, whisk together flour, sugar, cocoa powder, baking soda, and salt.  

In medium bowl, whisk together hot water, oil, vinegar, and vanilla.  

Pour the liquid mixture into the dry ingredients and whisk together until well blended. 

Pour the batter into the cake pan and bake until a toothpick inserted in the center comes out clean, about 30-35 minutes.

Let the cake cool completely on a wire rack. 

Once completely cooled, crumble the cake with your fingers or a fork and place in a bowl for assembly.

In the bowl of a stand mixer, beat heavy cream until soft peaks form. 

In a large mixing bowl, combine the cream cheese, peanut butter, sugar, and vanilla until blended and smooth. 

Gently fold the whipped cream into the peanut butter mixture until no white streaks remain and your mixture is fully combined and a uniform light brown color. 

Gently fold in the chopped Reese’s Peanut Butter Cups. (The rest will be for sprinkling on top when assembling)

Place the chocolate in a small bowl. Heat the cream in a small saucepan to just about boiling, but not boiling. 

Pour the hot cream over the chocolate and let it sit for 1 minute undisturbed. 

Begin stirring the mixture with a spatula, starting in the center and making small circular motions. Continue stirring towards the outer edges of the bowl. Stir until a thick ganache forms and the mixture is fully combined. Cool until ganache is thickened and pourable/spoonable. 

Line up your jars (or cups). 

Have all your ingredients ready to go.

Layer jars as follows: cake crumbles, peanut butter cheesecake filling, ganache, crushed peanuts, and chopped Reeses’s peanut butter candies.

Start by adding the cake crumbles to the bottom of each jar. 

Next, add peanut butter cheesecake filling. Fill a Ziploc sandwich bag with the peanut butter filling and cut one corner off. Squeeze in the filling on top of the cake crumbles then use a spoon to press the mixture down as evenly as possible.

If the inside sides of the jar get a little messy, this is fine. However, if it bothers you, dampen a very small piece of paper towel, wrap it around your finger, and wipe the inside of the jar as best you can. 

Next, add the ganache with a small narrow spoon. The ganache should stay below the narrower top of the jar. This will ensure you have room for crushed peanuts and candies before twisting the lids on. 

Sprinkle on your crushed peanuts and chopped Reeses’s candies.

Twist on the lids. Refrigerate until ready to serve.