In a small bowl, whisk together the yogurt, lemon juice, cumin, and coriander. Place the chicken in a shallow, airtight container and pour the marinade over top, turning to coat the chicken. Cover the container and let the chicken marinate in the refrigerator for at least 1 hour or up to 6 hours.
Pull the chicken out of the refrigerator and preheat the oven to broil on high. Line a baking sheet with foil and set a wire rack in the baking sheet. Remove the chicken from the container, shaking off any excess marinade, and lay them on the wire rack in a single layer, about 1 inch apart. Broil for 5 to 6 minutes, then flip the thighs and broil for another 5 to 6 minutes. The chicken is done when an instant-read thermometer inserted into the thickest part of a thigh registers 165°F. Remove the chicken from the oven and set them aside to cool.
Preheat the oven to 500°F (if using a baking sheet) or as high as it will go (if using a baking stone/steel; place the stone/steel in the bottom third of the oven before you start preheating). Let the oven preheat for at least 30 minutes. Then, if you’re using a baking stone or steel, switch the oven to Broil on high.
While the chicken cools, prepare the sauce. Melt the butter in a medium saucepan over medium-high heat. Add the onion and sauté for 5 to 7 minutes or until they begin to soften. Add the garlic and ginger and sauté for 1 minute, then stir in the tomato paste, ½ tablespoon of garam masala, paprika, and cayenne and cook for another minute. Stir in the tomatoes with their juices, reduce the heat to low, and simmer for 5 minutes or until the sauce comes to a bubble and begins to thicken.
Chop the chicken into ½-inch pieces and add them to the sauce, along with the 6 tablespoons of heavy cream. Let the sauce come back to the simmer, then add the salt and a few grinds of black pepper, taste, and adjust seasonings as necessary. Stir in ¼ cup of cilantro and remove the pan from the heat. Let it cool slightly while you stretch or roll out the dough.
Stretch or roll out your dough to a 12- to 14-inch circle, then transfer it to an oiled or parchment-lined baking sheet or a lightly floured pizza peel (if using a baking stone/steel).
Spoon the chicken and sauce onto the dough, spreading it out evenly and leaving a ½-inch border of dough all around. Brush the exposed edges of dough with a little melted butter if desired.
Transfer the pizza to the oven and bake until the crust is golden and the toppings have browned in spots—8 to 10 minutes on the baking sheet, 6 to 8 minutes on the baking stone/steel. Remove the pizza from the oven.
As soon as the pizza comes out of the oven, drizzle it with the remaining 1 tablespoon of cream. Let the pizza rest for 5 minutes, then sprinkle with the remaining 1 teaspoon of chopped cilantro; slice and serve.