1. Heat a Dutch oven over medium-high heat. Add oil to pan; swirl to coat. Add salt, peppers, and shallots; cook 3 minutes or until shallots begin to brown. Reduce heat to medium-low; cook, covered, 20 minutes or until peppers are tender.
2. Increase heat to medium-high. Add vinegar, sugar, and thyme; cook 15 minutes or until peppers are tender and shallots are golden brown, stirring occasionally. Serve warm or at room temperature.