Heat the oil in a large skillet or pot over medium heat.
Add the diced onion and sauté for 5 minutes, until softened and translucent.
Stir in the garam masala, tomato paste, grated ginger, and minced serrano chile.
Cook for 1 minute more, stirring constantly, until the spices are wonderfully fragrant.
Season with salt and pepper.
Add the rinsed chickpeas and crushed tomatoes to the skillet.
Stir to combine, bring to a boil, then reduce the heat to medium-low.
Let it simmer for 15 minutes for the flavors to meld together.
Remove the skillet from the heat.
Stir in the Greek yogurt and chopped cilantro until just combined.
Serve immediately.
Adjust the heat to your liking. For a spicier curry, leave the seeds in the serrano or add a pinch of red pepper flakes. For zero heat, omit the chile entirely.
