Preheat the oven to 375 degrees (350 for dark or nonstick pans).
Stir the cookie mix, butter, and water together in a medium bowl until a stiff dough forms. Press the dough into a lightly greased 8x8 pan. Cook for 12 minutes until set (note: the cookie dough will not be completely cooked). Remove from the oven and allow to cool while you prepare the cheesecake layer.
Mix the cream cheese and sugar together in a large bowl until smooth. Add the sour cream, eggs, and vanilla. Mix until combined, scraping the sides of the bowl occasionally as you mix. Spoon the cheesecake batter on top of the cookie crust.
Bake for 35-40 minutes or until the filling is set but still soft in the center. Remove from the oven and cool for at least 30 minutes. Refrigerate until ready to serve.
When ready to serve, cut into 2” x 2” squares, dust with sifted powdered sugar and Christmas sprinkles (I used red and green sugar and gingerbread man sprinkles).
Notes
This cheesecake is actually better if allowed to sit for 24 hours. It becomes more creamy during the resting time.If you’re unsure whether the filling is set, use an instant read thermometer to check. The temperature about one inch from the edge should be about 180 degrees.