Preheat your oven to 350°F.
In a small bowl, combine the graham cracker crumbs, sugar, and melted butter.
Press the crumb mixture into the bottom of a 9-inch springform pan.
In a large mixing bowl, beat the cream cheese until smooth.
Gradually add the sugar and flour, beating until well combined.
Add the eggs, one at a time, beating well after each addition.
Stir in the lemon juice, lemon zest, and poppyseeds.
Pour the mixture into the prepared pan.
Bake for 45-50 minutes, or until the center is set.
Allow the cheesecake to cool to room temperature before slicing and serving.