Preheat the oven to 425°F (220°C). Wash and dry the potatoes, then cut larger ones in half or quarters for even cooking.

Toss the potato pieces with 2 tablespoons olive oil, 1/2 teaspoon salt, 1/4 teaspoon black pepper, and half the thyme. Spread in a single layer on a rimmed baking sheet.

Place the tray in the oven and roast for 25-35 minutes, turning once at 15-20 minutes, until golden brown and soft.

In a large skillet, heat 1 tablespoon olive oil over medium-high heat. Add mushrooms in a single layer and let them sit undisturbed for 3–4 minutes to brown.

Stir and cook an additional 2–3 minutes until they have brown edges and a nutty aroma.

Add garlic to mushrooms and cook for 30–60 seconds until fragrant. Stir in remaining thyme and smoked paprika, if using.

Reduce heat to medium and add spinach in batches, stirring until wilted but still bright green.

Once potatoes are roasted, mix them with the mushrooms and spinach or place the mushroom-spinach mix on the tray with potatoes. Finish with lemon juice or vinegar and Parmesan if desired.