Heat olive oil in a skillet and sauté the chopped onion until soft and translucent. This process adds sweetness and removes the raw onion bite. Add garlic and cook briefly until fragrant, then stir in the spinach. Make sure the spinach is fully squeezed dry before adding to prevent watery filling. Finally, mix in chopped artichokes and cook for a few minutes until well combined.
Transfer the spinach mixture to a bowl and let it cool slightly. Add cream cheese, mayonnaise, Parmesan, mozzarella, and red pepper flakes if you like a little heat. Season with salt and pepper, then mix everything until creamy and well combined. Taste the filling and adjust seasoning to your liking before moving on.
Preheat the oven to 375°F (190°C) and line your baking sheet with parchment paper. Roll out the pizza dough into a large rectangle on a lightly floured surface. Spread the creamy spinach artichoke filling evenly across the dough, leaving a small border along the edges. Roll the dough into a tight log, then seal the edge to hold everything together.
Using a serrated knife, cut the rolled dough into 1-inch slices. Place each swirl on the prepared baking sheet, spacing them apart. Brush the tops with egg wash to create a golden crust, and sprinkle with everything bagel seasoning if desired. Bake for 20–25 minutes until golden brown and bubbling. Let them cool slightly before serving.