Rinse the quinoa in a fine-mesh sieve under cold water until the water runs clear — this removes bitter saponins and prevents a soapy flavor. Drain well.

Combine the rinsed quinoa and 340 ml water (about 2¼ cups) in a medium saucepan with a pinch of salt. Bring to a gentle boil uncovered, then immediately reduce to the lowest simmer and cover. Cook for 12–15 minutes until the water is absorbed and the germ has spiraled out of the grain. Why: a low, steady simmer prevents the grains from breaking and gives light, separate flakes rather than gluey quinoa.

Remove the quinoa from the heat and let it sit, covered, for 5 minutes to steam. Then uncover and fluff with a fork — fluffing separates grains and releases trapped steam so the quinoa cools quickly and remains airy. Transfer to a large shallow bowl to cool while you prepare the rest of the salad; spreading it thin helps it cool faster so it won't wilt the spinach.

While the quinoa cooks, pat the chicken breasts dry and season both sides generously with salt and pepper. Rub one tablespoon (15 ml) of the olive oil over the chicken. Why: drying the surface promotes browning; oil helps conduct heat and prevents sticking.

Heat a cast-iron skillet or heavy nonstick frying pan over medium-high heat until hot — you want a shimmering surface. Add the chicken and sear without moving for 3–4 minutes until golden-brown, then flip and reduce heat to medium. Cook another 4–6 minutes, or until the internal temperature reaches 74°C (165°F). Why: a hot pan creates a Maillard crust that adds savory depth and locks in juices; finishing on medium heat cooks through without burning the exterior.

Transfer the chicken to a cutting board and let rest for 6–8 minutes before slicing. Why: resting lets the juices redistribute so the meat stays moist when sliced.

Make the lemon-parsley dressing: in a small bowl whisk together the juice and zest of 1 lemon, the remaining 15 ml (1 tbsp) olive oil, most of the chopped parsley (reserve a tablespoon for garnish), a pinch of salt and several grinds of black pepper. Taste and adjust — the lemon should be bright but balanced. Why: emulsifying oil and acid binds the dressing; fresh parsley and lemon brighten the whole salad.

Assemble the salad base: to the cooled quinoa add the baby spinach, halved cherry tomatoes, diced cucumber, red bell pepper, and thinly sliced red onion. Toss gently with about three-quarters of the dressing so the quinoa absorbs flavor but the vegetables keep some texture. Why: tossing while quinoa is slightly warm helps it take on dressing flavors but not so hot that it wilts the spinach completely.

Slice the rested chicken thinly on the bias and arrange over the quinoa-vegetable mixture. Crumble the feta over the top and drizzle any remaining dressing over the chicken. Finish with the reserved chopped parsley and a little fresh lemon zest for aroma. Why: slicing on the bias gives longer, elegant pieces that look great and provide a larger surface area for each bite.

Serve warm or at room temperature. If making ahead, store dressing separately and toss just before serving to keep textures bright. Why: chilled dressing on cold quinoa can firm up the olive oil and mute flavors — tossing just before serving preserves the salad's freshness.