Crust

1. In a medium mixing bowl (preferably metal or glass), mix warm water with the yeast and salt. You don’t need to wait for it to bubble but will know immediately by the “yeasty” smell if it’s active. Stir in 2 1/4 cups spelt flour with a wooden spoon, then add the remaining 1/4 cup flour, if needed, until dough is cohesive enough to knead. Turn out onto a lightly floured (with more spelt flour) surface and knead vigorously (excellent video tutorial!) for a few minutes, adding more flour if the dough remains sticky, until it forms a smooth ball that’s only a little sticky. Drizzle the olive oil into the mixing bowl, add the ball of dough, turn to coat, and cover tightly with plastic wrap. Set in a warm place to double in size, one to two hours. If you don’t have a really warm spot, the dough may take a little longer to double, but it should still rise.
2. Turn the dough out onto a clean, lightly floured surface and knead a couple times. Either refrigerate the ball, wrapped in plastic, until ready to use (up to two days) or proceed with assembly.

Filling

1. Toss the broccoli, pepper, and onion in about a tablespoon of olive oil, salt, and pepper to coat and spread on a sheet pan. Roast at 425 on the top middle rack until slightly browned and just tender. Once cool, roughly chop the veggies.
2. Combine roasted veggies with both kinds of cheese and half the beaten egg, plus a generous sprinkle of salt and pepper. Set aside while you roll out the calzone dough.

Assembly

1. Move oven rack to the middle position and increase heat to 450. Clean sheet pan from the roasted veggies and line with parchment paper.
2. Divide the calzone dough into 4 or 6 approximately equal pieces. Roll each into a ball, then, on a lightly floured surface, use a rolling pin to roll each ball into a circle that’s thin, but that you can still handle. As you finish, transfer each round onto the baking sheet, with part of the circle hanging off the edge of the sheet.
3. Spoon about 2/3 cup of filling onto half of each dough round, leaving about an inch of space between the filling and the edge. Brush that gap lightly with water, lift the “empty” side of the dough up and over the filling, and gently press the edges together to seal. You can also gently press the sealed edge with a fork. When all the calzones are filled, Brush tops thinly with the remaining beaten egg and sprinkle with a little salt.
4. Bake calzones for 12 to 15 minutes, until beginning to brown on top and dough is firm and sounds hollow when tapped. Let cool slightly before serving with warm marinara sauce.