1. Roast the tomatoes. On a sheet pan, gently toss together the tomatoes, peppers, onion, garlic, thyme, 2 tablespoons olive oil, vinegar, and salt and pepper to taste. Arrange the tomatoes and red peppers, skin side up, tucking the garlic bits beneath them and bake until lightly charred, 45 to 50 minutes.
2. Build the soup. In a soup pot, warm the remaining 2 tablespoons of the olive oil over medium-high heat. Stir in the tomato paste and mix well, cooking until it's a deeper red than when you started, about 5 minutes. Add the tomato and pepper mixture, including the juices, and combine. Stir in the stock, cover, and bring to a boil. Reduce the heat to low and simmer for 20 minutes. Let cool for 5-10 minutes. Transfer the soup to a blender* (or use hand-held immersion blender) and pulse in small batches that reach only about a third to halfway up the side of the jar. When blending start slow then increase the speed to puree the ingredients until smooth. Use a separate bowl to hold the blended soup and then return it all to the pot.
3. Stir in the Hidden Valley®. While whisking, slowly add the Hidden Valley® Original Ranch® Light Dressing until combined. Serve warm.