In a small bowl, with your mixer at low speed, beat the butter, flour, sugar and 1 egg yolk until well mixed into a dough. Cover the dough and refrigerate for 1 hour.

Preheat the oven to 400°F.

Press 1/3 of the dough into the bottom of a 10 inch spring form pan. Reserve the remaining dough in the refrigerator. Bake the bottom crust for 8 minutes, then cool it.

Turn the oven down to 475°F.

Meanwhile, melt the chocolate chips in a small pot over boiling water so the chocolate won't burn.

In a large bowl with the mixer at medium speed, beat the cream cheese until smooth. Reduce speed to low, gradually beat in 1 3/4 cups sugar, 3 tablespoons flour, the melted chocolate and the rest of the ingredients, except cream, until it is all blended together. Beat at high speed for 5 minutes.

Press the reserved dough around the side of the spring form pan to within 1 inch of the top. Pour the cheese mixture into the pan and bake for 12 minutes. Turn the oven down to 300°F and bake for another 50 minutes. Turn the oven off and leave the cheesecake in the oven for 30 minutes. Cool it in the pan on a rack for 30 minutes.

Refrigerate, covered until ready to serve. Looks wonderful garnished with whipped cream, and chocolate shavings.