I found this recipe in the New York Times Magazine's February 2008 Column "The Way We Eat". This recipe was adapted from Centro Vinteca in Manhatten. Pasta suggestions to serve with this recipe are bucatini, pappardelle, or pici.
Using a food processor, puree the onion, carrots, celery and garlic to a coarse paste.
Coat a large pan generously with olive oil and set over medium heat. Add the pureed vegetables, season with salt and cook until all of the water has evaporated and the vegetables begin to brown, about 15-20 minutes. Stir frequently and be patient. (This is where the big flavours develop.).
Add the ground lamb, season generously with salt and cook until it is browned, about 25-30 minutes. (Brown food tastes good; don't rush this step.).
Add tomato paste and cook for about 5 minutes. Stir in the red wine, rosemary and bay leaves. Cook at a lively simmer until the wine has reduced by half. Add the thyme bundle and enough water to cover the lamb( about 1 inch). Simmer for 3 to 4 hours, stirring and tasting frequently and adding more water as it evaporates. Skim the fat off the surface. Remove the bay leaves and the thyme. Season to taste with salt and pepper.
Toss with al dente pasta (see pasta suggestions in the recipe description) and serve with freshly grated Parmesan cheese.