Preheat oven to 350°F.
Spray an 8 by 11 inch pan with nonstick cooking spray. Set aside.
In a large bowl, blend the flour with the baking powder, baking soda, salt, corn syrup, white and brown sugar. Cut in the butter until the mixture resembles a fine meal. Turn out into the baking pan and drizzle in cream and vanilla and toss by hand to combine until you have a slightly, damp, sandy mixture. Press or pat gently into the pan. Bake until edges are barely browned, 20-25 minutes. Remove and spread on the caramel.
Prepare the caramel while the bottom layer is baking.
In a medium saucepan, stir the condensed milk, corn syrup, butter, and brown sugar over low heat. Simmer, stirring once in awhile, 8-10 minutes, until mixture does not taste gritty (sugar dissolves), and is thickened and about 245°F Be careful that the bottom does not burn. If this happens do not stir the burnt part into the rest of the caramel. Pour caramel over baked (very warm, or still hot) cookie bottom.
Place the chocolate bars on the caramel. Using a metal icing spatula, apread the chocolate over the caramel to cover the top. Alternatively, chop the chocolate and sprinkle over the top (or use milk chocolate chips but chocolate bar chocolate tastes better), let melt a bit and then coat the top.
Refrigerate a few hours to let the chocolate set. Remove from the fridge, bring to room temperature, then cut into finger sizes.