For the chicken curry: Toss the chicken thighs with the lemon juice and some salt in a large bowl. Set aside for 30 minutes.
Toast the cashews (including some for garnish) in a small saucepan over low heat and set aside. Dry roast the coriander, cumin, cardamom, peppercorns and cloves in a small skillet over low heat. Let them cool before grinding them in a spice grinder. Set aside.
Add the onions, garlic and ginger to a blender and puree until smooth. Heat the vegetable oil in a large saucepan over medium heat. Add the onion mixture and the bay leaves to the oil and cook, stirring occasionally, until the onion mixture is golden brown, about 15 minutes.
Fill a medium saucepan with water and bring it up to a boil. Score the bottom of each tomato with a paring knife and drop them in the hot water for 15 seconds. Remove from the water and peel off the skins. Place the peeled tomatoes in a blender and puree until smooth. Add them to the onion mixture along with the cayenne, cinnamon, turmeric, marinated chicken thighs, toasted and ground spice mixture and some salt. Turn the heat to medium-low and cook, stirring occasionally, until the tomatoes begin to turn into a smooth, loose paste and the oil begins to separate from the mixture. Cover and cook, stirring occasionally, about 20 minutes more.
Add the cream, 1 cup of cashews and some salt to a blender and puree until smooth. Add the cashew cream to the chicken and tomato mixture and stir to incorporate. Keep warm until ready to serve.
For the onion bread: Preheat the oven to 450 degrees F and line a baking sheet with parchment paper.
Place the chopped onions on a baking sheet and roast in the oven until slightly browned, less than 5 minutes. Mix in the chiles if using, and set aside.
Combine the flour and 1/4 teaspoon of salt in a large mixing bowl. Add the ghee and just enough water until a dough forms. Start to knead and punch the dough, adding more water if necessary. The dough should be smooth and soft. Use your hands to form the dough into 6 to 8 medium balls. Take one dough ball at a time and roll it into a 3- to 4-inch disc on a floured surface. Spoon some of the onion and chili mixture into the center along with a pinch of cilantro, if using, and some more salt. Fold the dough over on itself, bringing the edges together to form a half circle. Sprinkle some more flour on the board and roll the stuffed dough into a 6- to 8-inch disc.
Heat 1 or 2 teaspoons of ghee in a large skillet over medium-low heat. Fry the bread in batches until the bottom is evenly browned; add 1 or 2 more teaspoons of ghee and flip to brown the other side, less than 2 minutes per side.
To serve: Chop the reserved toasted cashews. Divide the chicken curry among bowls and top with the cashews. Serve with the hot onion bread.