Heat the olive oil in a large deep skillet or pot over medium-high heat.
Place the chicken drumsticks in the pan and sear until golden brown on all sides, approximately 6 minutes, then remove and set aside.
In the same pan, add the diced onion and sauté for 4 minutes until softened and translucent.
Stir in the minced garlic and grated ginger, cooking for 1 minute until fragrant.
Add the turmeric, garam masala, sea salt, and black pepper, stirring constantly for 30 seconds to toast the spices.
Pour in the crushed tomatoes and coconut milk, whisking gently to create a smooth sauce.
Return the chicken drumsticks to the pan, nestling them into the sauce.
Reduce heat to low, cover with a lid, and simmer for 20 to 25 minutes until the chicken is fully cooked and tender.
Serve the curry in a deep bowl over the warm basmati rice and garnish with fresh chopped cilantro.