Pat the chicken breast dry with paper towels. Rub with 1 tablespoon olive oil, 1/2 teaspoon salt, 1/4 teaspoon black pepper and 1/4 teaspoon dried oregano (if using).

Cook

Heat a skillet over medium-high heat. When hot, add the chicken and cook 5–7 minutes per side (depending on thickness) until golden and internal temperature reaches 165°F (74°C). Reduce heat if chicken browns too quickly.

Rest & Slice

Transfer chicken to a cutting board and let rest 5 minutes. Slice thinly or chop into bite-sized strips. Keep warm or set aside to cool slightly before adding to salad.

Toast Walnuts

Place walnuts in a dry skillet over medium heat. Toast, stirring frequently, 3–5 minutes until fragrant and lightly browned. Remove from heat and let cool; coarsely chop.

Make Blackberry Vinaigrette

Place 3 ounces fresh blackberries in a blender or food processor. Add 2 tablespoons red wine vinegar, 1 teaspoon honey (or maple), 1/2 teaspoon Dijon mustard, 1/2 teaspoon salt and 1/4 teaspoon black pepper. Pulse to break down berries.

With the blender running, drizzle in 4 tablespoons extra-virgin olive oil to emulsify. If the dressing is too thick, add up to 1 tablespoon warm water and pulse once more to reach a pourable consistency. Taste and adjust seasoning or sweetness. If desired, strain through a fine mesh sieve for a smooth vinaigrette, pressing solids to extract as much liquid as possible.

Prepare Produce & Assembly

Wash and dry the spring mix, arugula, blackberries and blueberries. Gently pat berries dry to avoid breaking them.

Slice the cucumber in half lengthwise, thinly slice crosswise and place in a bowl. Halve, pit and dice the avocado; toss lightly with a squeeze of half a lemon to prevent browning (optional).

In a large bowl, combine 4 cups spring mix and 1 cup arugula. Add the sliced cucumber, diced avocado, 1/2 cup blackberries and 1/2 cup blueberries.

Drizzle about half of the blackberry vinaigrette over the salad and gently toss to coat. Add more dressing to taste — you will likely use between 3–5 tablespoons depending on preference.

Arrange sliced chicken on top of the dressed greens. Sprinkle 1/2 cup crumbled feta and 1/2 cup toasted chopped walnuts evenly over the salad. Garnish with extra 1/4 cup berries for visual contrast.

Serve immediately, passing remaining vinaigrette on the side.