Start by mixing the graham cracker crumbs with melted butter and a bit of sugar. The mixture should look like wet sand and hold together when pressed. Spoon it into lined muffin cups and press firmly to create an even base.
In a bowl, beat the softened cream cheese until smooth. Add sugar gradually, then mix in eggs, lemon juice, zest, vanilla, and sour cream. The batter should be silky and lump-free before moving on.
Spoon the cheesecake filling over the crusts, filling each cup almost to the top. Add small drops of raspberry preserves on the surface. Use a toothpick or skewer to gently swirl for a marbled look.
Place the muffin pan in a preheated oven and bake until the centers are just set. They should still have a slight jiggle in the middle. Overbaking can cause cracks, so keep an eye on them.
Let the cups cool at room temperature before refrigerating. Chilling for at least two hours helps the cheesecake firm up and develop full flavor. This step makes a big difference in texture.