Coat non-stick skillet with pan spray. Heat over medium-high heat, add onions and sprinkle with salt. Cook until onions start to brown, about 4 minutes, stirring occasionally.
Add 1/2 cup water and stir. Cook another 2 minutes until almost all of water has cooked out.
Add dressing, stir and reduce heat to medium low. Cook 15 minutes, stirring occasionally.
Remove from heat and strain to remove excess liquid. Transfer to small bowl and stir in dry mustard.
• Serve with Panera Bread® Seared Sirloin and a crumble of blue cheese for a fabulous meal.
• Great as a pizza or flatbread topping.