Prepare the filling by first cooking the spinach according to the instructions on the package. Once cooked, press the spinach into a colander to drain out as much liquid as possible. Set spinach aside. (Tip: Press spinach with paper towels to soak up the extra liquid.)
Using a large sauté pan, add ½ Tbsp of olive oil and place over medium heat. Once hot, add onions and garlic; cook for 4-5 minutes, stirring often.
Add lemon juice, cheeses, sour cream, cream cheese, chopped artichokes, 1 tsp of kosher salt, paprika and drained spinach; stir until well combined. Reduce heat to medium-low and continue cooking until mixture begins to simmer (~5 minutes).
Preheat oven to 500°F.
Working on a well-floured cutting board or counter top, roll/flatten 1 piece of dough into an 8” round circle. (Note: Keep the remaining dough covered while working. Use additional flour as needed to ensure dough does not stick.)
Place ~½ cup of the spinach artichoke filling into center of the dough.
Using a small bowl, whisk together egg with 1 Tbsp of water. Lightly brush the edge of half of the dough with the egg mixture. Fold dough in half and crimp edges with a fork to seal. Place calzone on a lightly oiled baking sheet.
Repeat process using remaining dough, filling and cheese. (see note)
Cut 2-3 small vents into the top of each calzone to let steam escape.
Using a small bowl, combine the Italian seasonings with the remaining 2 Tbsp of olive oil, remaining ½ tsp of kosher salt Brush the tops of the calzones with this herbed olive oil mixture.
Bake for 10-12 minutes, or until calzones are golden brown in color.