In a 6-qt. pot over medium-high heat, cook onion with oil and 1/2 tsp. salt until onion is soft, about 2 minutes. Reduce heat to medium and cook, stirring occasionally, until onion starts to brown around the edges, about 5 minutes.
Add garlic, ginger, green onions, and jalapeño. Increase heat to high and cook, stirring, until fragrant, about 1 minute. Add coriander and cayenne and cook, stirring, 30 seconds. Reduce heat to medium-high and stir in yogurt. Add tomatoes and 1 cup water. Bring to a boil, then reduce heat to maintain a steady simmer. Cook until flavors blend and sauce thickens a bit, about 10 minutes.
Stir in garam masala and add salt to taste. Set eggs, cut side up, on sauce. Spoon a bit of sauce over each egg and cook without stirring until hot, about 2 minutes. Serve garnished with cilantro if you like.
Note: Nutritional analysis is per serving.