Heat the skillet over medium and add a teaspoon of cumin seeds. Let them crackle for about 30 seconds until fragrant.
Add the chopped onion to the pan and sauté, stirring often, until golden and caramelized, about 8 minutes. The onion should smell sweet and turn a rich amber color.
Stir in the minced garlic and cook for another 30 seconds until fragrant, enhancing the aroma of the dish.
Add the turmeric, coriander powder, and garam masala, stirring constantly for about 1 minute until the spices toast and release their fragrant aroma, making the mixture darker and more aromatic.
Pour in the crushed tomatoes and cook, stirring occasionally, until the oil begins to separate from the sauce and it deepens in color, about 10 minutes. The gravy should smell rich and smoky.
Add the shrimp to the pan, gently stirring to coat them evenly with the masala. Cook for 3-4 minutes, until the shrimp turn pink and are just cooked through.
Squeeze in the lemon juice and stir. Taste and adjust salt or spice as needed. If the sauce is too thick, add a splash of warm water and simmer briefly until it reaches your desired consistency.
Turn off the heat and sprinkle with chopped cilantro. Let it sit for a couple of minutes to meld the flavors.
Serve hot over steamed rice or with flatbread, enjoying the vibrant, glossy sauce and tender shrimp in every bite.
