My husband is a cheesecake fiend! According to him, this is the best cheesecake he's ever eaten, and considering he orders cheesecake everywhere we go, that's saying something! I am a huge chocolate fan, so we get along just fine with this one.
Crush the oreos and mix with melted butter. Press into bottom of 10 inch springform pan. Bake 10 minutes in 325 oven. Cool slightly before adding cheesecake mixture.
In large mixing bowl, beat softened cream cheese until smooth. Add eggs, one at a time, as you continue beating. Add Irish cream and vanilla next, continue beating. Add flour and sugar, about half at a time, beating until fully incorporated.
Melt chocolate chips and add to cheesecake mixture while the mixer is running. This is the tricky part, as the chocolate will immediately start to set when it hits the cold batter, so keep that mixer moving!
Bake in 325 oven 55-60 minutes or in a 300 oven 60-65 minutes if using a dark nonstick pan. Is done when center is almost set and just before edges start to crack. Allow to cool completely before releasing the springform pan and transferring to a serving plate. Refrigerate to store, up to 3-4 days (if it lasts that long!).