Saute peppers, garlic, and cumin in olive oil for one minute; increase heat to high; stir in wine, boil and cook until reduced to 1/2 cup. Add stock, and boil to reduce to 1 cup, stirring constantly.
Lower heat. Add tomatoes and cook down. Add 2 tablespoons of butter, stirring constantly until melted. Add 2 more tablespoons of butter, stirring until the sauce thickens. Remove from heat. Add cilantro