butter and sugar in a small bowl, and toss with a fork.
Press mixture over the bottom of a 9" springform pan.
Bake the crust until it is crisp and golden in color, about 10 minutes.
Reduce the heat to 300F.
Place a roasting pan or baking dish filled with hot water on the bottom rack of the oven to create moisture. For the cake filling, cream the cream cheese in a medium size mixing bowl with an electric mixer on medium speed for 1 minutes.
Scrape the sides of the bowl.
Add brown sugar and beat on medium-high until the cream cheese is fluffy, about 1 minute. Scrape the bowl.
Add eggs and vanilla, and beat on medium-low speed until smooth, about 45 seconds.
Scrape the bowl.
Add flour, and mix on low speed about 5 seconds.
Add the pecans and mix to blend, 15 to 20 seconds.
Pour the filling over the crust. Bake the cake on the center oven rack until the top is set, about 1 3/4 hours.
Remove from oven, allow to cool on a wire rack for 1 1/2 hours, then refrigerate overnight. Two hours before serving the cake, prepare the topping.
Place the brown sugar, cream and butter in a small saucepan over medium heat and stir until the sugar is dissolved.
Bring the mixture to a boil and continue to boil for 1 1/2 minutes, stirring occasionally.
The mixture will look like a thick golden syrup.
Remove the pan from the heat and pour the topping into a small bowl to stop the cooking process.
When it stops bub bling, pour it over the cheesecake. Tip the springform pan from side to side so that the topping coats the cake evenly.
Keep the cake at room temperature until ready to serve.