Preheat oven to 350 degrees F (175 degrees C). Line 18 muffin cups with paper liners.
Beat cream cheese in a bowl using an electric mixer until smooth; add eggs, 1 at a time, ensuring each is fully incorporated before adding the next. Beat 1 cup sugar and 1 1/2 teaspoons vanilla extract into cream cheese mixture until mixture is smooth; fill muffin cups to within 1/8 inch of the top.
Bake in the preheated oven until set in the middle, about 35 minutes.
Mix sour cream, 2 tablespoons sugar, and 1/4 teaspoon vanilla extract together in a bowl. Drop a teaspoonful of sour cream mixture over cupcakes.
Bake cupcakes in the oven for 5 minutes more. Cool cupcakes to room temperature and refrigerate until chilled.
