Preheat the oven to 225°C. Line a baking sheet with parchment paper.

Rinse the lentils in a colander under cold water and drain well. Spread them on the baking sheet and pat dry with paper towels.

Wash and chop the bell peppers, then add them to the lentils. Season with oil, salt, black pepper, and harissa. Roast in the oven for about 12–15 minutes, or until the lentils are lightly browned and slightly crisp.

Prepare the vinaigrette. Grate the zest of the washed orange into a small bowl and squeeze in the juice. Add white wine vinegar, Dijon mustard, salt, black pepper, and sugar. Slowly pour in the oil in a thin stream while whisking constantly.

Rinse the spinach in a colander under cold water and let it drain. Peel and cut the oranges into segments.

Bring water to a boil for the bulgur. Cook the bulgur about 10-15 minutes. Fluff the cooked bulgur with a fork and transfer to a bowl. Mix in the vinaigrette, spinach, and orange segments.

Serve the bulgur salad with the roasted vegetables.