Preheat oven to 325 degrees. Spray a 12-cup fluted cake pan with nonstick cooking spray with flour.

In a large bowl, beat butter at medium speed with an electric mixer until creamy. Add sugars; beat until fluffy. Add eggs, one at a time, beating well after each addition.

In a medium bowl, combine flour, baking powder, and salt. Gradually add to butter mixture, 1 cup at a time, alternately with milk, beginning and ending with flour mixture. Beat just until combined. Stir in toffee bits and pecans. Spoon batter into prepared pan.

Bake for 1 hour and 15 to 25 minutes, or until a wooden pick inserted in the center comes out clean. Cover top of cake with aluminum foil to prevent excess browning if necessary.

Let cool in pan for 10 minutes. Remove from pan and cool completely on a wire rack. Spoon Caramel Drizzle over cooled cake.

In a medium saucepan, combine milk and brown sugar; bring to a boil over medium-high heat, whisking constantly. Reduce heat, and simmer for 8 minutes, whisking constantly. Remove from heat; whisk in butter and vanilla. Let cool for 5 minutes.