Prep the chicken: If the breasts are uneven in thickness, butterfly or gently pound them to an even thickness of about 1/2–3/4 inch (12–18 mm). This ensures even cooking so the thinner parts don’t overcook while the thicker parts finish. Pat the chicken dry with paper towels to help the marinade adhere and to promote browning on the grill.

Make the lemon-garlic marinade: In a shallow bowl or zip-top bag whisk together 2 tbsp (30 ml) olive oil, 2 tbsp (30 ml) lemon juice, lemon zest, minced garlic, 1/2 tsp kosher salt, 1/4 tsp black pepper and 1/2 tsp dried oregano. Reserve the remaining dressing ingredients for the salad dressing (see step 6). Marinate the chicken for 20–30 minutes at room temperature (or up to 2 hours in the fridge). Why: the acid and oil in the marinade flavor the meat and the short marinating time (not too long) prevents the lemon from tightening the proteins and making the meat tough.

Rinse and toast the quinoa: Place the dry quinoa in a fine-mesh sieve and rinse under cold water for 30 seconds to remove the natural bitter coating (saponin). Drain well. In a medium saucepan, heat 1 tsp olive oil over medium heat and add the quinoa; toast, stirring, for 1–2 minutes until it smells nutty. Toasting blooms the grain’s flavor and gives a more complex taste than boiling straight away.

Cook the quinoa: Add 2 cups (480 ml) water and a pinch of salt to the toasted quinoa, bring to a gentle boil, then reduce to a low simmer, cover tightly and cook 15 minutes. Turn off the heat and let it sit, covered, for 10 minutes to steam. Fluff with a fork. Why: the long rest lets trapped steam finish cooking the quinoa, yielding light, separate grains instead of gummy quinoa.

Grill the chicken: Heat a gas or charcoal grill to medium-high (about 400°F/200°C) or heat a grill pan over medium-high heat with a light brush of oil. Remove excess marinade from the chicken (so it’ll sear, not steam). Grill the breasts 4–6 minutes per side, turning once, until you have good char and the internal temperature reaches 165°F (74°C). Why: a hot grill creates Maillard browning (complex savory flavors) and quick cooking preserves juiciness. Use an instant-read thermometer for accuracy.

Make the dressing: While the quinoa cooks, combine the remaining 2 tbsp (30 ml) olive oil, 1 tbsp (15 ml) lemon juice, a small pinch of lemon zest, the remaining minced garlic, 1/2 tsp kosher salt and 1/4 tsp black pepper and 1/2 tsp dried oregano in a jar and shake or whisk until emulsified. Taste and adjust salt/acid. Why: emulsifying oil and acid coats salad ingredients evenly and melds flavors.

Assemble the quinoa salad base: While the quinoa is still slightly warm (this helps it absorb flavors), transfer it to a large bowl. Add the halved cherry tomatoes, diced cucumber, thinly sliced red onion, and half the crumbled feta. Toss with about 2/3 of the dressing (reserve the rest to dress the greens or to finish the dish). Why: mixing warm quinoa with the dressing opens the grains to absorb flavor; holding back some dressing prevents overdressing the greens later.

Rest and slice the chicken: Transfer the grilled chicken to a cutting board and tent loosely with foil for 5 minutes. Resting redistributes juices so the chicken stays moist when sliced. Slice the breasts thinly across the grain for a tender bite.

Plate: Divide the mixed salad greens among four shallow bowls. Spoon a generous portion of the quinoa-vegetable mixture on top of the greens. Fan sliced grilled chicken over each salad and sprinkle with remaining feta. Drizzle any remaining dressing over the chicken and greens, finish with a grind of black pepper and (optional) a light drizzle of olive oil and a little extra lemon zest for brightness.

Serve and store: Serve immediately. Leftovers keep well: store components separately (chicken sliced, quinoa salad, dressing) in airtight containers for up to 3 days—this keeps greens from wilting and flavors bright.