To make the espresso peanut butter, combine all ingredients in a small bowl.
To make the mac and cheese, bring a large saucepan of water to the boil. Once boiling, add pasta and cook for 3/4 of the recommended time on the pasta pack. Drain and set aside.
Meanwhile, to make the cheese sauce melt butter in a medium sized saucepan over medium heat. Add flour, whisking well and allowing to cook for about 1 min before adding milk, 1/4 cup at a time, whisking well between each addition until all milk is incorporated and you have a smooth sauce. Add cheese. Stir well until cheese melts and sauce becomes oozy. Season to taste with salt and white pepper then add the pasta and stir to coat.
Next, grill the bacon until crispy and the patty until cooked to your liking.
To assemble the burger, spread the espresso peanut butter on the base, top with patty, cheese, bacon and sliced pickles. Add a spoonful of mac and cheese on the top and sprinkle with fried shallots before adding the top of the bun. Serve immediately.
