To enrich the flavor of diced tomatoes, roast them: Drain one 28 oz. can diced tomatoes in a colander, reserving juices.  Shake out excess juices before placing drained tomatoes on 2 layers of parchment paper on a sheet pan.  Stir in 2 tsp. olive oil.  Roast on the middle rack of a preheated 375°F oven for 40 minutes without stirring.  Use in your favorite sauce recipes with or without the reserved juices.