Dough:

1. In a large bowl mix together the flour and salt.
2. In a separate bowl or jar heat the filtered water to 95℉ (35°C). Add the instant yeast and mix until dissolved. Pour the yeast-water into the flour mixture and mix until a shaggy dough forms. 
3. Turn the dough out onto a work surface and knead lightly for 1-2 minutes until smooth.
4. Place in a large bowl and cover with plastic wrap. Let rise at room temperature for 18-24 hours.
5. On a lightly-floured work surface, dump out the dough and divide into 4 equal pieces. Working with one piece at a time, stretch and pull the sides over itself and then roll over, placing it seam-side-down. Turn the dough in a circular motion between the palms of your hands, keeping the dough in constant contact with the work surface, to create a taut ball. Repeat with the remaining dough. 
6. Place the dough balls onto a flour-dusted baking sheet and cover with an inverted baking sheet. Let rest at room temperature for 4 hours.

‍Tomato Sauce:

1. In a medium saucepan, add the olive oil and heat over medium heat. Add the garlic and cook for 1-2 minutes, swirling the pan occasionally, until the garlic is toasted to a light golden brown.
2. Add the crushed red chili flakes and toast for 20 seconds before adding the canned tomatoes. Stir in a pinch of sugar to curb the acidity and bring to a simmer.
3. Reduce the heat to low and allow the sauce to reduce for 8 minutes, stirring occasionally. 
4. Season to taste with salt and pepper.

‍Filling:

1. In a medium skillet, add the oil and heat over medium heat until shimmering.
2. Add in the onion and peppers and lightly toss. Season, to taste, with salt and pepper and cook, stirring occasionally, for 4-5 minutes, or until the vegetables are cooked through and have a light char to them.
3. In a medium bowl combine the mozzarella and Parmigiano cheese. Set aside. 

‍Assembly:

1. Place a proofed ball of dough onto a lightly-floured pizza peel and press the dough down, shaping it into a disc. Then stretch or roll it out into a larger disc measuring ⅓” (8.5mm) thick.
2. On the bottom half of the dough, top with a few slices of salami, some grated cheese, a layer of peppers and onions, more cheese, another few slices of salami and then a final sprinkling of cheese (being careful not to overstuff).
3. Carefully grab the top layer of the dough and drape it over the lower half, covering the fillings. Pinch together the edges of the dough and then fold the edge back over itself in the opposite direction creating a lip. Press the edge again to create a double seal. 

‍To bake in a Conventional Oven:

1. Set a pizza stone in a 500℉ (260℃) oven and preheat for 45 minutes prior to baking.
2. Once assembled, slide the calzone onto the hot pizza stone and bake in the oven for 8-12 minutes until the dough is fully cooked through and the crust is golden brown.
3. Remove from the oven and top with the tomato sauce, freshly grated Parmigiano Reggiano, a glug of olive oil and fresh basil.

‍To bake in a Wood-fire Pizza Oven:

1. Preheat the single-serving wood-fired pizza oven (such as Ooni brand) according to manufacturer’s instructions.
2. Carefully slide the calzone onto the stone surface, close the door and bake for 1-2 minutes. Turn the calzone 180° and bake for 2 more minutes. Remove from the oven.
3. To serve, top with tomato sauce, freshly grated Parmigiano Reggiano  cheese, a glug of olive oil and fresh basil.