In a large bowl, beat butter and sugars with a mixer at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition.
In a medium bowl, whisk together flour, baking powder, and salt. Gradually add flour mixture to butter mixture alternately with milk, beginning and ending with flour mixture, beating at low speed just until combined after each addition. Stir in toffee bits and pecans.
Spray a 12-cup Bundt pan with baking spray with flour. Spoon batter into prepared pan.
Bake until a wooden pick inserted near center comes out clean, 1 hour and 15 minutes to 1 hour and 25 minutes, covering with foil to prevent excess browning, if necessary. Let cool in pan for 10 minutes. Remove from pan, and let cool completely on a wire rack. Spoon Caramel Drizzle over cooled cake.
Caramel Drizzle
In a medium saucepan, bring condensed milk and brown sugar to a boil over medium-high heat, whisking frequently. Reduce heat, and simmer for 8 minutes, whisking frequently. Remove from heat; whisk in butter and vanilla. Let cool for 5 minutes before using.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/brown-sugar-pound-cake/