01 - Preheat the oven to 425°F. Line a baking sheet with parchment paper.
02 - Wash the bell peppers, cut into quarters, and remove seeds. Arrange on the prepared baking sheet and roast for 20 minutes until the skins are blistered and the flesh is tender. Let cool slightly, then slice into strips.
03 - While the peppers roast, rinse quinoa thoroughly under cold water. Combine quinoa, water, and 1/2 teaspoon salt in a saucepan. Bring to a boil over medium-high heat, then reduce to low, cover, and simmer for 15 minutes until the liquid is fully absorbed. Remove from heat and fluff with a fork.
04 - In a large salad bowl, whisk together the olive oil, lemon juice, Dijon mustard, minced garlic, salt, and pepper until well emulsified.
05 - Add the cooked quinoa, roasted pepper strips, sliced red onion, halved cherry tomatoes, and chopped parsley to the bowl. Toss gently until everything is evenly coated with the dressing.
06 - If desired, sprinkle crumbled feta cheese and toasted pine nuts over the top. Serve warm or at room temperature.