For my family, Lamb has always been one of four ways. As a stand alone meat with no type of sauce, au jus, with a tomato coulis, or crusted in some way. Typically since it is always served rare. Most people prefer mint jelly (never understood that one, bleech). Lamb stew was always the exception being cooked tender and in a brown gravy. But tha was also flavored with the lamb and veg so.........
You could try this sauce....... I would primarily serve it with veal in a dish called Veal Marengo but found it to work equally well with lamb. I have no direct mesurments since this was one I would just "wing". But since your not making it by the gallon.........I'll try to provide some adequate measurments for use in the home.
Olive oil. 1/4 cup
Mushrooms, button, quartered. 2 cups
Shallots, minced fine. 1ea
Garlic Clove, minced fine. 2ea
Tomatoes, Roma, fresh, peeled and seeded. 7lbs (Since good fresh tomatoes are not really available this time of year you may substitute 1-16oz can diced and 1-16oz can crushed.)
Kalamata olives, pitted and sliced. 1 cup
Basil, fresh cut, chiffonade. 1/2 cup
Fresh cream (optional) 1 cup
Heat large sauce pan over med high flame. Add olive oil, and mushrooms. Saute for 1 minute. Add garlic and shallot. continue to cook for 2 minutes being careful not to burn garlic and shallots.
If you have an immersion blender, continue to puree the 1 can of crushed tomatoes until more sauce like but not as smooth. The same is done with the diced but only to remove the large pieces. (You can also use a blender or food processor to puree the crushed and mash the diced with your hands or a potato masher to achieve the same effect)
Add these to the mushroom/garlic and shallots. Continue to heat mixture to a boil and reduce heat to simmer and cook for 20 minutes. Stir frequently.
Add sliced Kalamata olive and continue to cook for an additional 15 minutes. stirring frequently. At this piont I would add the cream and basil and adjust salt and pepper for taste. It can be held warm for service later or used immediately.
Hope this helps you out.