While the pizza dough rests, make the saag (greens). Heat oil in a pan, add the onion and cook till it turns translucent. Add garlic and ginger and cook for 30 seconds or until fragrant. Add red chili powder, garam masala, salt and pepper.
Squeeze out the excess water from spinach and add it to the onion mixture. Cook till all of the moisture from spinach evaporates, about 2~3 minutes.
Remove from heat and add cream and lemon juice. Stir to combine. Taste and adjust the seasoning.
Roll the dough out into 1 12~13" round pizza or 2~3 6~8" round pizzas. Place them on a lightly greased baking sheet or preheated baking stone. Divide the spinach mixture among the pizza bases and spread into an even layer, leaving about ½" border. Sprinkle with cheese.
Bake 1 baking sheet at a time until the cheese is melted and the crust is cooked through, about 8~10 minutes. Remove from the oven, let cool for couple of minutes before slicing and eating.