In a bowl, combine 220g bread flour, 220g water (at 95°F), and 1/4 teaspoon instant yeast. Cover with plastic wrap and let sit at room temperature for 14 to 18 hours.
In a stand mixer bowl, add 375g bread flour and 12g fine sea salt. Mix together.
Add poolish mixture to the flour and salt in the stand mixer.
Dissolve 1/2 teaspoon instant yeast into 257g water (at 95°F) and add to the mixer.
Mix for 5-6 minutes until the dough starts to pull from the sides of the bowl.
Coat a large bowl with non-stick spray, add dough, cover with plastic wrap, and let rise for 1 hour.
Place a baking steel or pizza stone in the middle rack of your oven and a cast iron skillet at the bottom. Preheat to 450°F.
Stretch and fold the dough by picking up a piece with damp hands, stretching to its max without tearing, folding it over itself, and repeat around the perimeter.
Cover the dough and let rest for 25 minutes.
Repeat stretching and folding two more times, resting for 25 minutes between each fold.
After last fold, cover and let rise for 45 minutes until dough is smooth.
Generously flour a work surface and carefully dump dough onto it, forming a rough rectangle without degassing.
Split dough lengthwise with a bench scraper.
Cut each segment into three even pieces, you should have six pieces.
Gently cover the pieces with an inverted container and let rest at room temperature for 30 minutes.
Load three to four pieces onto a piece of parchment paper with at least 2 inches of space between them.
Add one cup of ice cubes to the scorching hot cast iron pan and quickly load the parchment paper with dough onto the baking steel or stone, spray the oven and loaves with water (not the glass).
Close the oven door and bake for 15 minutes, then remove the steamer and bake for another 5 to 8 minutes until golden brown.
Cool the bread to room temperature.
In a small bowl, combine 120g mayonnaise, 30g sriracha sauce, 3 grated garlic cloves, salt to taste, and the juice of half a lemon. Stir together to make spicy mayo.
Slice 2 large tomatoes into 1/2 inch slices.
Heat a large pan with vegetable oil over medium-high heat. Once hot, sear the tomato slices for 1 to 2 minutes per side until browned and lightly charred.
In the same pan, add more oil if needed and heat over medium-high. Add slices of Mortadella and sear for 1 minute per side until hot and slightly browned. Repeat with remaining slices.
In the same pan, heat more oil over medium-high. Crack in the eggs and cook until the whites are set, then swirl the pan or flick some oil on top to finish cooking.
Toast the shabata buns to perfection.
Spread a generous layer of spicy mayo on both sides of the toasted bun.
Add one layer of cheddar cheese and one layer of Gouda cheese to the buns.
Broil or blow torch the cheese until melted and slightly charred.
Layer the seared tomatoes, Mortadella, and fried eggs onto the bottom bun.
Scatter fresh basil leaves on top.
Top with the other half of the bun and serve immediately.