Rinse the baby spinach and mixed lettuces under cold water, then spin or pat dry thoroughly. Place greens in a large salad bowl. Add the chopped parsley and torn basil and gently toss to combine.

Mushrooms

Prepare mushrooms

Wipe mushrooms clean with a damp cloth or quickly rinse and pat dry. Slice cremini and shiitake mushrooms to about 1/4-inch thickness.

Sauté mushrooms

Heat a large skillet over medium-high heat. Add 2 tbs olive oil and 1 tbs butter (if using). When the fat is hot and shimmering, add the sliced mushrooms in a single layer. Avoid overcrowding; sauté in batches if needed so they brown rather than steam. Let mushrooms cook without stirring for 2–3 minutes to develop color, then stir and continue cooking 3–4 more minutes until golden and reduced.

Finish mushrooms

Lower heat to medium, add the minced garlic and thyme and cook 30–45 seconds until fragrant. Season with 1/2 tsp salt and 1/4 tsp pepper (reserve remaining salt/pepper for the salad). Taste and add up to 1/4–1/2 tsp more salt if needed. Remove from heat and let cool slightly.

Dressing

In a small bowl or jar combine 3 tbs extra-virgin olive oil, 2 tbs lemon juice, 1 tsp Dijon, 1 tsp honey or maple, 1 tsp red wine vinegar, 1/2 tsp salt and 1/4 tsp black pepper. Whisk or shake vigorously until emulsified. Taste and adjust acidity or seasoning to preference.

Assemble & Serve

Once mushrooms are slightly cooled but still warm, add them on top of the dressed greens. Pour the dressing over the salad and toss gently to coat greens and mushrooms evenly.

Scatter toasted nuts, crumbled goat cheese (if using), and sliced red onion over the salad. Finish with a small sprinkle of lemon zest if desired and a final grind of black pepper.

Serve immediately so the warm mushrooms slightly wilt the greens, or refrigerate the mushrooms first for a cold mushroom-and-greens salad.