Preheat an oven to 350 F. Grease and line an 8x8" baking pan with parchment paper so that extra parchment hangs over the edges. This makes it easier to remove the cheesecake from the pan.

To make the cookie crumbs, pulse 15-20 gingersnap cookies in a food processor until the crumbs are very fine. Combine with the other ingredients with a fork until the mixture looks like wet sand. Using a measuring cup, press the crust into the prepared pan in an even layer so that they're packed tight.

Bake for 10 minutes and cool to room temperature. REDUCE the oven to 300 F. 

In a small saucepan, combine all the ingredients and cook over low heat for 20 minutes, stirring occasionally, until the sauce is thick and the cranberries are very soft. Cool before using.

Combine the cream cheese and sugar in a mixing bowl. Using a hand mixer, beat until the cream cheese is very smooth and fluffy, about 4-5 minutes. Add the eggs, sour cream, vanilla, and Grand Marnier and mix until the filling is very smooth and all the ingredients are well combined.

Cool to room temperature and then refrigerate covered for at least 4 hours before cutting and serving. Use the overhanging parchment paper to remove the cheesecake from the pan before cutting it into squares.