Step 1

Line a standard muffin pan with paper liners. Set aside.

Step 2

In a large bowl, add chocolate and vegetable oil. Melt the chocolate using a double boiler or in the microwave on 50% power in 30 second increments, stirring the mixture between each stint in the microwave. The chocolate should be completely melted and smooth.

Step 3

Add 1 heaping teaspoon of melted chocolate to each paper liner and use the back of the measuring spoon or a small spatula to spread the chocolate up the sides of the liner about 1/2 inch.

Step 4

Place the muffin pan in the fridge to quickly set the chocolate while you prep the fillings.

Step 5

In a small bowl, add peanut butter, confectioners' sugar, and vanilla. Use a handheld electric mixer to beat the mixture on medium speed until well blended. Set aside. Add the peanut butter mixture to a small piping bag (either fitted with a medium round tip or simply with the end of the bag cup open in a small circle) and set aside.

Step 6

Break graham cracker cookies into 1 inch square pieces and set aside. (If using store-bought graham crackers that come in rectangular sheets each made up of 4 smaller rectangles, breaking each of the smaller rectangles in half will yield the correct size pieces. You should get 8 squares per rectangular graham cracker sheet.)

Step 7

Add marshmallow creme to a small piping bag (either fitted with a medium round tip or simply with the end of the bag cup open in a small circle).

Step 8

Pipe a circle of marshmallow creme onto the center of the chocolate in each of the paper liners, leaving 1/4 inch of chocolate exposed around the edge.

Step 9

Place a graham cracker square onto the marshmallow creme in each cup.

Step 10

Pipe a circle of peanut butter filling on top of each graham cracker square, again leaving 1/4 inch around the edge.

Step 11

Spoon a heaping Tablespoon of melted chocolate onto each peanut butter cup and use the back of the measuring spoon or a small spatula to gently spread the chocolate over the top of the filling and down the sides so it meets the chocolate at the bottom of the liner, sealing the filling within the chocolate cup.

Step 12

Lightly crush flaky sea salt between your fingers and sprinkle a bit over each cup.

Step 13

Place the muffin pan in the fridge for at least 15 minutes to quickly set the chocolate. Remove the paper liners before serving.