Pour 1 cup water into the InstantPot and place the wire metal steam rack in the pot.
Line the bottom of a 7-inch cake pan with a removable bottom with parchment paper. Coat the sides of the pan and the parchment paper with cooking spray.
To prepare the crust: In a food processor, pulse the graham crackers a few times, until small crumbs form. Add the melted butter and pulse until just combined. Pour the graham cracker mixture into the prepared pan and evenly press onto the bottom. Freeze the crust for 20 minutes while you prepare the filling.
To prepare the filling: Wipe the food processor bowl and blade clean with a paper towel to remove any crumbs. Add the cream cheese, the 1/2 cup mango pulp, the sugar, and flour and pulse until smooth, a few seconds; do not overmix. Add the eggs and yolk, one at a time, and pulse one or two times after each addition until just combined. Again, be careful not to overmix. Gently stir the filling with a rubber spatula until well combined.
Pour the filling into the frozen crust. Tap the pan gently on the countertop so that any air bubbles in the batter rise to the surface. Most of the air bubbles will burst as you tap the pan but if not, burst them with a tooth pick. This helps getting a smoother surface.
Drizzle with the remaining 1 1/2 teaspoons mango pulp and gently swirl through the batter with a wooden skewer; be sure to burst any air bubbles. Cover the top of the pan with a paper towel and place an 8-inch sheet of aluminum foil over the top, crimping down the foil around the sides of the pan to secure the paper towel in place. Place the pan on the rack in the Instant Pot.
Secure the lid and set the Pressure Release to Sealing. Select the Pressure Cook or Manual setting and set the cooking time for 37 minutes at high pressure.
Let the pressure release naturally; this will take 10 to 15 minutes. Open the pot and, wearing heat-resistant mitts, lift out the cake pan. Remove the foil and paper towel, then dab off any liquid that may have accumulated on top of the cheesecake with another paper towel. Do not worry if a 1-inch circle in the middle of the cake is a bit jiggly; the cake will continue to cook as it cools.
Let the cheesecake cool on the counter for about 1 hour.
To remove the cheesecake from the pan, carefully run a butter knife around the inside edge of the pan and down the sides. If your pan is a push pan type, place it on an empty glass cup and gently push down on the top edges of the pan. This will help the cake to release from the pan sides. If using a springform pan, unclasp the collar on the pan and lift it off. Transfer the cheesecake to a platter. Refrigerate for at least 6 hours and up to 5 days.
Cut into wedges and serve cold.