Stir together flour, yeast, and salt in a mixing bowl. Stir in olive oil and then add water, mixing on medium speed with a dough hook. You can also mix the dough with a large spoon until it comes together and then knead it for about ten minutes until it’s smooth. If you’re using a dough hook, mix dough on medium for 8-10 minutes. If at any point the dough is very wet and sticky, add more flour by the tablespoon. If the dough is very dry and cracking, add more water by the tablespoon.
When dough is ready, add to a lightly oiled bowl, cover, and let rise for two hours.
For filling:
Stir together cheeses, yolk, and oregano in a medium bowl. Set aside.
Remove casing from sausages and add to a large skillet with a drizzle of oil over medium-high heat. Cook until browned nicely, breaking up the sausage as it cooks. It should take 8-10 minutes to cook through.
Add garlic to sausage and cook for just a minute. Then add washed and chopped chard. Cook until it wilts down, about 5-6 minutes. Season with a pinch of salt and pepper.
Making Calzones:
Preheat oven to 400 degrees Fahrenheit. If you have a pizza stone, heat the stone in the oven also.
Divide dough into six even pieces (about 5-6 ounces each). Roll each piece of dough out until it’s a 7-8 inch circle. Add a sixth of the cheese mixture (about a third of a cup) to half of the bread. Then top with a sixth of the sausage mixture.
Fold dough over and try to press out as much air as possible. Seal edges well by rolling them over. Brush calzone with olive oil and sprinkle with kosher salt. Cut a few slices in the top of the calzone so steam can escape.
It’s easier to transfer the calzone in and out of the oven if you put it on parchment paper. Slide the calzone in and bake for about 25 minutes at 400 degrees until the calzone is a deep golden brown and cooked through. Remove and let cool for a minute or two before serving.
Extra calzones can be reheated in the oven for 15-20 minutes at 350 degrees or you can freeze them as well. If you freeze them, you should be able to transfer them straight from the freezer to the oven but you’ll have to reheat them for an extra 10-15 minutes.