Line the bottom of a springform pan with parchment paper. Press 8 rugelach into the bottom of the pan until they form a crust with no space between the rugelach. Carefully line the sides of the pan with more rugelach then gently press together.
Make filling: Using an electric mixer, beat the cream cheese, sour cream, sweetened condensed milk, vanilla and lemon juice. Scrape down the sides of the bowl and blend until smooth and creamy. Add the eggs, one at a time, and beat until eggs are incorporated.
Make chocolate swirl: melt the chocolate chips and oil in a microwave, stirring every 30 seconds until completely smooth.
Pour half of the cheesecake filling into the rugelach crust. Pour half of the chocolate over the filling and swirl with a toothpick. Top with the remaining filling then swirl in the remaining chocolate.
Place the cheesecake on a baking sheet and bake for 1 hour. Turn off the oven and leave the baked cheesecake in the oven for 1 hour to avoid cracking on the top of the cake. Refrigerate cake in the pan for 3-4 hours before removing the mold and slicing.