Beat cream cheese and sugar with an electric mixer on low speed until smooth and lump free. Approximately 3 minutes.
Add 2 Tablespoons of flour and beat until incorporated.
Add sour cream, vanilla and lemon juice then beat until combined.
Add eggs, one at a time, beating on low for a few seconds after each addition until just combined. For best results, avoid overbeating eggs.
Divide batter evenly among two bowls.
Pour the batter for the plain cheesecake onto the graham cracker crust.
Add the cooled raspberry syrup and 1 Tablespoon of flour to the remaining bowl of batter and stir until evenly combined.
Gently spoon raspberry cheesecake batter on top of the plain cheesecake batter.
Bake for 65 - 75 minutes or until the cheesecake's edges are set and the center is no longer jiggly. Keeping cheesecake in the oven and the door ajar with a wooden spoon, turn oven off and allow cheesecake to cool in the oven for 1 hour.
Remove cheesecake from the oven. Place springform pan on a wire rack to cool to room temperature then cover and refrigerate for a minimum of 4 hours before slicing and serving.
Garnish with fresh raspberries if desired. Cheesecake will keep covered in the refrigerator up to 3 days.