In a large deep skillet, heat the oil over medium-high heat. Add the chicken and cook for 4 minutes until lightly browned. Remove chicken and set aside.
In the same pot, add the sliced onions and sauté for 5 minutes until softened and caramelized. Add the garlic and ginger and cook for 1 minute, until fragrant. Stir in the garam masala, cumin, coriander, paprika and cayenne. Cook for 1 minute.
Add the rice and chicken broth. Bring to a boil, then reduce heat to low, cover and simmer for 15 minutes.
Remove from heat and fluff the rice with a fork. Fold in the chicken, cilantro and lemon juice. Season with salt and pepper.
Garnish with extra cilantro, if desired.