Cut a circle of parchment paper to fit the bottom of a 7-inch springform pan.

In a bowl, mix the graham cracker crumbs, butter, and sugar until the mixture resembles wet sand. Press firmly into the bottom and up the sides of the pan.

Place the crust in the freezer while preparing the filling.

In a large bowl, beat the cream cheese until fluffy. Add the sugar, flour, lemon zest, lemon juice, and sour cream, and mix until smooth.

Add the eggs one at a time, mixing after each addition until fully incorporated. Pour the filling into the prepared crust.

In a food processor, blend the raspberries and sugar until smooth. Drop spoonfuls over the cheesecake and use a butter knife to gently swirl.

Cover the pan tightly with foil and poke a small hole in the center to allow steam to escape.

Pour 1 cup of water into the Instant Pot. Place the cheesecake on the trivet and lower it into the pot.

Seal and cook on high pressure for 55 minutes. Allow the pressure to release naturally, then release any remaining pressure. Remove the cheesecake, take off the foil, and let it cool on a wire rack.

Lightly beat the eggs to combine.

In a saucepan, combine the eggs, sugar, lemon zest, and lemon juice. Cook over medium-low heat, stirring constantly, until the mixture becomes creamy. Reduce the heat to low and continue cooking until thickened enough to coat the back of a spoon.

Remove from heat and stir in the butter until fully blended. Let the topping cool.

Spread the cooled lemon topping over the cooled cheesecake. Arrange fresh raspberries on top.

Chill thoroughly before slicing. Store leftovers in the refrigerator.