Roasted Vegetable Stew

This vegan stew gets its rich flavor from mushroom stock and roasted vegetables. Serve with crusty bread or ladled over rice or couscous.
1 large sweet potato (8 oz.), peeled and cut into 1-inch chunks
1 small head cauliflower (about 2 1/2 lbs.), cut into 1 1/2-inch flowerets (about 6 cups)
2 lemon slices, cut 1/4-inch thick
1/2 medium onion, cut into thin wedges
2 garlic cloves, minced
4 Tbsp. olive oil, divided
Salt and ground black pepper
8 oz. cremini (baby Portobello) mushrooms, sliced in half
1 carton (32 oz.) College Inn® Bold Mushroom Stock
6 oz. green beans, trimmed and cut in half (about 1 1/2 cups)
2 sprigs fresh oregano or 1 sprig fresh rosemary
2 cups baby spinach (about 2 oz.)
Heat oven to 450°F. Place sweet potato, cauliflower, lemon, onion and garlic on a rimmed baking sheet. Drizzle with 2 Tbsp. oil and season with salt and pepper; toss to combine and spread into an even layer. Roast about 30 minutes until vegetables are browned and tender.
Meanwhile, heat remaining 2 Tbsp. oil in a 4 or 5-qt. saucepan or Dutch oven over medium-high heat. Add mushrooms and sear 5 minutes. Add stock, green beans and oregano and bring to simmer over high heat. Simmer over medium heat about 8 minutes until green beans are tender. Remove from heat.
Add roasted vegetables to stock. Simmer 3 minutes over medium-high heat. Remove lemon slices and oregano sprigs and gently stir in spinach. Season with salt and pepper to taste.