Preheat the oven to 350°F. Grease and flour three 8-inch cake pans.

In a large bowl, whisk together the sugar, flour, cocoa powder, baking soda, baking powder, and salt for 1 minute.

With the mixer on low speed, add the softened butter a few pieces at a time until the mixture resembles coarse sand. Scrape the sides and bottom of the bowl.

In a separate bowl, whisk together the eggs, milk, vegetable oil, and vanilla extract until well combined.

Gradually add about half of the egg mixture to the dry ingredients while mixing on low speed. Increase the speed to medium and mix for 1 1/2 minutes. Scrape the bowl, then add the remaining egg mixture in two additions, mixing for 20 seconds after each addition. Scrape the bowl again.

Slowly add the hot coffee and mix for another 30 seconds until blended. The batter will be runny.

Divide the batter evenly among the prepared pans. Sprinkle half of the chopped pecans and toffee bits over the top of the batter in each pan. Reserve the remaining pecans and toffee bits for later.

Bake for 25-30 minutes or until a toothpick inserted in the center comes out clean. Cool the cakes in the pans for 10 minutes, then turn out onto wire racks to cool completely.

Dissolve the instant espresso coffee in the hot water and set aside to cool slightly.

Beat the softened butter on medium speed until smooth. Add the vanilla extract, cocoa powder, and salt, and mix until combined.

Gradually add half of the powdered sugar and half of the coffee mixture, beating on medium speed until incorporated.

Add the remaining powdered sugar and coffee mixture, and continue to beat on medium speed for 3-6 minutes, scraping the sides of the bowl occasionally.

If the frosting is too thin, add more powdered sugar. If too thick, add a bit more hot water or milk, a teaspoon at a time.

This recipe makes enough frosting to fill, frost, and decorate a three-layer 8-inch cake.