Shake Shack Potato Buns:

1. In the bowl of a stand mixer fitted with the dough hook, evenly combine the flours, dry milk powder, amylase, sugar, and salt.
2. Place the water in a microwave safe bowl and heat until it is 90℉ (32℃). 
3. In a small bowl, whisk together the warm water and yeast until the yeast dissolves. Whisk in 1 egg until homogenous. With the mixer running on low speed add the yeast mixture and stir for 2-3 minutes or until a rough dough forms.
4. Add the softened butter and mix for another 2-3 minutes or until the dough is smooth. Place the dough on a clean work surface and form into a ball. Place in a greased bowl, cover with plastic wrap and let rise for 1 hour at room temperature or until doubled in size.
5. Punch down the dough and divide it into 8 even pieces, about 120g each. Shape the dough pieces into balls, and place them on a sheet pan lined with parchment paper. Cover with greased plastic wrap and proof again at room temperature for 30-45 minutes or until doubled in size.
6. When the dough is almost done rising, preheat the oven to 375℉ (190℃).
7. In a small bowl whisk together the remaining egg and a splash of water until homogenous. 
8. Brush the tops of the dough with the egg wash and bake for 15-17 minutes or until golden brown. Remove from the oven and immediately brush the tops with melted butter if you would like. Set aside.

Steak N Shake Burger Blend:

1. Cut the T-bone, short rib, and chuck in even strips.
2. Using the medium grinding plate on a meat grinder, grind all of the meat 2 times.
3. Shape patties into 2.5-3oz (70-85g) balls, and reserve for cooking later.

In-N-Out Burger Sauce:

1. Begin by preheating a small saucepan over medium heat.
2. Once hot add butter to the pan and let it melt. Once the butter has melted add the diced onion and season lightly with salt.
3. Allow onions to cook, constantly stirring, until they are caramelized and deep brown in color.
4. In a medium bowl, add in all the ingredients besides onions and stir until well combined.
5. Once combined, add in the caramelized onions and stir to combine.

Assembly:

1. Begin by toasting the bun in a large saute pan set over medium heat with some melted butter.
2. While the bun is toasting, begin preheating a griddle or cast iron skillet over medium-high heat.
3. Remove the toasted bun from the pan and place onto a plate. Reduce heat on the griddle to medium.
4. Place burger balls onto the griddle and smash until a ¼” (6mm) thick. Season with salt to taste and let cook for 45 seconds to 1 minute.
5. Flip and top 1 patty with American cheese. Then place your burger patties on top of each other and allow the cheese to melt.
6. While the cheese is melting sauce the top and bottom buns, and lay the sliced pickles over the bottom bun.
7. Add the cooked patties over the pickles and top the burgers with fresh sliced onion. Finish with the top bun. Repeat making the remaining burgers. Serve and enjoy!