Roasted Sweet Potato, Spinach, Caramelized Onion, Feta & Walnut Bake

Description

This colorful vegetable bake combines tender roasted sweet potatoes, soft caramelized onions, wilted spinach, creamy feta, and crunchy walnuts. The sweet potatoes develop golden edges in the oven, while the onions add a rich sweetness that balances the salty cheese. A little garlic, thyme, and lemon bring everything together without overpowering the vegetables.

This recipe is inspired by the dish pictured, with thick sweet potato rounds, visible onion slices, and a generous scattering of feta and walnuts. Serve it as a vegetarian main course or alongside roasted chicken, fish, or lentils.

Prep Time: 20 minutes
Cooking Time: 50–60 minutes
Total Time: 70–80 minutes
Servings: 6 as a side dish or 4 as a main course
Oven Temperature: 400°F / 200°C conventional, or 180°C fan

Ingredients

For the Roasted Sweet Potatoes

• 3 medium sweet potatoes, approximately 900 g
• 1½ tablespoons olive oil
• ½ teaspoon smoked paprika
• ½ teaspoon dried thyme
• ¼ teaspoon salt
• ¼ teaspoon black pepper

For the Onions and Spinach

• 2 large yellow onions
• 1 tablespoon olive oil
• 1 tablespoon butter
• 3 garlic cloves, finely chopped
• 250 g fresh spinach, washed and thoroughly dried
• ¼ teaspoon salt, or to taste
• ¼ teaspoon black pepper
• 1–2 tablespoons water, as needed

For Assembling and Finishing

• 150 g feta cheese, crumbled
• ½ cup walnuts, roughly chopped
• 1 tablespoon fresh lemon juice
• 1 teaspoon fresh thyme leaves, plus extra for serving
• A little olive oil or butter for greasing the baking dish

Step-by-Step Instructions

1. Prepare the Sweet Potatoes

Preheat the oven to 400°F / 200°C. Line a large baking tray with baking paper and lightly grease a 9 × 13-inch baking dish.

Scrub the sweet potatoes and peel them if desired. Cut them into even rounds approximately 1 cm thick so they cook at the same rate.

Place the rounds in a large bowl. Add the olive oil, smoked paprika, dried thyme, salt, and black pepper. Toss until evenly coated.

2. Roast Until Tender

Arrange the sweet potatoes in a single layer on the baking tray. Use two trays if necessary to prevent overcrowding.

Roast for 25–30 minutes, turning halfway through, until almost completely tender and lightly browned around the edges. A fork should slide into the centers with little resistance.

3. Caramelize the Onions

While the sweet potatoes roast, peel the onions. Cut them into thick rings or half-moons, approximately ½ cm thick. Rings create a finish closer to the photograph, although some will naturally separate during cooking.

Heat the olive oil and butter in a large skillet over medium-low heat. Add the onions and a small pinch of salt.

Cook for 25–35 minutes, turning or stirring gently every few minutes, until soft and golden. If the pan becomes dry or the onions begin to catch, add a tablespoon of water and lower the heat. Let the onions develop their natural sweetness gradually.

4. Wilt the Spinach

Transfer the cooked onions to a plate. Add the garlic to the same skillet and cook over medium-low heat for approximately 30 seconds.

Add the spinach in batches, tossing until wilted. Cook for another 1–2 minutes to allow excess moisture to evaporate. If liquid remains, drain it before assembling the bake.

Season with black pepper and a little salt, keeping in mind that the feta will add saltiness.

5. Assemble the Bake

Arrange half the roasted sweet potatoes in the prepared baking dish. Scatter over half the spinach, onions, and feta.

Repeat with the remaining sweet potatoes, spinach, onions, and feta. Keep a few golden onion rings visible on top for an attractive finish.

Drizzle with the lemon juice and sprinkle with fresh thyme.

6. Bake and Add the Walnuts

Bake uncovered for 10 minutes. Scatter the walnuts over the top, then return the dish to the oven for another 5–8 minutes.

The vegetables should be hot throughout, the feta lightly softened, and the walnuts fragrant. Watch the walnuts closely during the final minutes so they do not burn.

7. Rest and Serve

Allow the bake to rest for 5 minutes before serving. Finish with extra thyme and a little freshly ground black pepper.

Tips and Notes

• Cut even slices: Uniform sweet potato rounds roast more consistently.
• Avoid a watery bake: Dry the fresh spinach well and drain away any liquid after cooking.
• Use frozen spinach if needed: Substitute approximately 200 g frozen spinach, thawed and squeezed very dry.
• Give the onions time: Medium-low heat produces soft, golden onions without burning their edges.
• Add walnuts near the end: They toast quickly and can become bitter if baked for too long.
• Adjust the seasoning last: Taste the cooked vegetables before adding extra salt because feta brands vary in saltiness.
• Make it nut-free: Replace the walnuts with pumpkin seeds, or leave them out.
• Make it dairy-free: Use olive oil instead of butter and a suitable dairy-free feta alternative.

Serving Suggestions

Serve this bake with a crisp cucumber salad, warm wholegrain bread, or a bowl of lentils. It also makes a flavorful side dish for lemon chicken or baked fish.

For a more substantial vegetarian meal, fold 1½ cups cooked, well-drained chickpeas into the vegetable layers before baking.

Storage and Reheating

Cool the leftovers and refrigerate in an airtight container within 2 hours. Use within 3–4 days.

Reheat individual portions in the microwave or place the bake in a 350°F / 175°C oven, covered, until hot throughout. Uncover briefly at the end to refresh the topping.

For advance preparation, roast the sweet potatoes and cook the onions and spinach the day before. Refrigerate separately, then assemble and bake when ready. A chilled bake will need additional heating time; add the walnuts only during the final 5–8 minutes.

Frequently Asked Questions

Can I use another cheese?
Yes. Crumbled goat cheese works well. Mozzarella creates a milder, more melted topping, although it will change the flavor.

Do I need cream or eggs?
No. This is a layered roasted vegetable bake. The sweet potatoes, spinach, onions, feta, and walnuts provide plenty of texture without a creamy sauce or egg mixture.

Can I use regular potatoes?
Yes, but the flavor will be less sweet. Roast them until fork-tender before assembling, as their cooking time may differ.

Can I add the walnuts before serving instead?
Yes. Toast them separately in a dry skillet over medium-low heat, then sprinkle them over the finished bake.

Servings and Nutrition

Yield: 6 side-dish servings

Estimated nutrition per serving:

• Calories: 370 kcal
• Protein: 9 g
• Carbohydrates: 41 g
• Fat: 20 g
• Fiber: 7 g

Nutrition is approximate and varies with ingredient sizes and brands. Sweet potatoes provide beta-carotene and fiber, spinach contributes folate, and walnuts supply unsaturated fats.