Preheat oven to 300°F.

Combine the graham cracker crumbs, cocoa, sugar and melted butter and press evenly in the bottom of a 9 inch spring form pan.

In a large bowl, beat the cream cheese until fluffy.

Gradually add the sweetened condensed milk, beating until smooth

Add the eggs and vanilla; mix well.

In a small bowl, combine 1/2 the chocolate chips with the flour to coat. Stir into the cream cheese mixture.

pour into the pan and top with the remaining chocolate chips. Bake at 300°F for an hour to an hour and 10 minutes, until the cheesecake is set and not jiggly in the middle.

Turn the oven off, crack the door, and cool in the oven for 1 hour.

Remove from the oven and let stand until the pan is cool to the touch

Refrigerate for at least 4 hours.

Once chilled, remove from the pan by running a thin knife around the pan edge, and then carefully remove the spring form