Step 1-Grease the inside of the tart pan with vegetable oil & set it aside.
Step 2- Heat the chocolate in a heatproof bowl. Once melted, remove from heat and, stirring constantly, add the oil. Let it cool and stir it occasionally until the chocolate mixture becomes slightly firm.
Step 3- Pour a little less than half of the chocolate mixture into the tart pan. Save the remaining chocolate mixture at room temperature. Tilt pan until the bottom and sides of the pan is evenly coated with chocolate. Chill until firm.
Step 4- Meanwhile, purée the peanuts, powdered sugar, peanut butter, and salt in a mixer. Don’t make the paste too smooth.
Step 5- Transfer the peanut mixture to the tart pan that is already covered with the cooled chocolate. Flatten it to give a smooth finish.
Step 6- Pour the chocolate mixture that you kept aside over the centre of the peanut mixture layer. Tilt the pan to spread the mixture evenly. Chill the mixture for about 45 minutes until it becomes firm.
Step 7- Remove sides of the tart pan and carefully lift the giant peanut butter cup off the bottom of the pan. Let it sit at room temperature for 10 minutes, then cut it and it’s ready to serve.