Coat a 7-inch springform pan with non-stick spray and set it aside.

In a medium bowl, combine 1cupcrushed Oreo cookie crumbs, 1/4cupunsalted peanutsfinely crushed in the food processor, and 2tablespoonsunsalted buttermelted. Stir until evenly combined.

Press the crumb mixture firmly and evenly into the bottom and about 1 inch up the sides of the prepared springform pan. Place the pan in the freezer for 10 minutes to chill the crust.

While the crust chills, set the Instant Pot inner pot aside and measure 1 cup of water; you will add it later.

In a mixing bowl, beat 12ouncescream cheeseroom temperature and 1/2cupwhite granulated sugar at medium speed until smooth and no lumps remain. Scrape down the sides and bottom of the bowl as needed.

Add 1/2cupsmooth peanut butter, 1/4cupheavy cream, 1/4cupsour cream, 1teaspoonvanilla extract, and 1tablespoonall-purpose flour to the cream cheese mixture. Beat on low-to-medium speed just until combined, scraping the bowl once.

Add the 2eggsroom temperature one at a time, mixing briefly after each egg until just incorporated. Do not overmix.

Stir in 1/2cupsemisweet chocolate chips by hand to distribute evenly.

Remove the chilled crust from the freezer. Pour half of the cheesecake batter into the prepared springform pan and smooth the top gently.

Arrange the Reese’s cupsabout 6-7 over the batter in an even layer.

Pour the remaining batter over the Reese’s cups and smooth the top with a spatula.

Cover the springform pan tightly with aluminum foil.

Pour 1 cup of water into the Instant Pot inner pot. Place a trivet with handles inside the pot, set the covered springform pan on the trivet, and carefully lower it into the Instant Pot.

Lock the Instant Pot lid, set the valve to sealing, select High Pressure, and set the timer for 50 minutes.

When the cooking time ends, allow the pressure to release naturally for 10 minutes, then carefully perform a quick pressure release to release any remaining pressure.

When the valve drops, carefully remove the lid. Using an instant-read thermometer, check that the center of the cheesecake registers about 150°F and appears set (edges slightly puffed and center mostly set with a slight jiggle). If the center is not set, re-cover the pan with foil, lock the lid, set to High Pressure for 5 more minutes, then repeat the natural release for 10 minutes followed by a quick release. Recheck temperature.

Using the trivet handles, carefully remove the springform pan from the Instant Pot and place it on a wire rack. Remove the foil and allow the cheesecake to cool to room temperature.

Once cooled, cover the cheesecake with plastic wrap and refrigerate for at least 4–6 hours or overnight to fully chill and set.

When ready to top the chilled cheesecake, place 6ouncesmilk chocolatefinely chopped in a heatproof bowl. Heat 1/3cupheavy cream until it just begins to simmer (on the stove or in the microwave). Immediately pour the hot cream over the chopped milk chocolate and stir until the chocolate is completely melted and the ganache is smooth. Let the ganache cool slightly until it is pourable but not hot.

Pour the ganache over the chilled cheesecake, spreading it to the edges and allowing some to drip down the sides.

Sprinkle 1cupmini peanut butter cupscoarsely chopped on top of the ganache.

Refrigerate the finished cheesecake until the ganache is set and the cheesecake is fully chilled before slicing and serving.