In a large bowl, combine the first five ingredients. In another bowl, whisk egg, oil and buttermilk. Add to the dry ingredients and stir well. Slowly add the coffee until combined (batter will be thin).
Pour into a greased 13x9-in. baking pan. Bake at 350° for 35-40 minutes or until a toothpick inserted in the center comes out clean. Cool completely on a wire rack.
For frosting, melt butter in a small saucepan. Add the sugar and milk; bring to a boil. Reduce heat; cook and stir for 2-3 minutes. Remove from the heat. Add the melted chips and stir until blended. Pour over cake, spreading evenly. Drizzle with caramel topping and sprinkle with pecans.
TEST KITCHEN TIP To make drizzling easier, spoon caramel topping into a small resealable plastic bag and cut a small hole in the corner of the bag. Press topping out for an even and less messy drizzle.