In a medium-sized saucepan heat the oil over medium-high heat. When the oil is hot, add the onion and sauté until the onion is beginning to soften. Add the jalapeno and sauté for 2 minutes. Add the garam masala and cook for 1 minute, till the spices become fragrant. Add the ground lamb and add salt and pepper. Cook, stirring infrequently to ensure the lamb browns nicely, until the lamb is cooked through.