Best Green Bean Casserole Recipe: Nan Would Be Proud!

Ingredients

• 1.5 lbs (680g) fresh green beans, trimmed
• 1 tbsp (15 ml) olive oil
• Salt and freshly ground black pepper to taste
• 4 tbsp (56g) unsalted butter
• 1 large yellow onion, finely chopped (approx. 1 cup / 150g)
• 1 lb (454g) cremini mushrooms, sliced
• 2 cloves garlic, minced
• 1/4 cup (30g) all-purpose flour
• 2 cups (475ml) vegetable broth
• 1/2 cup (120ml) heavy cream
• 2 tbsp (30ml) dry sherry (optional)
• 1/4 tsp ground nutmeg
• 1/4 tsp ground thyme
• 3 large shallots, thinly sliced
• 1/2 cup (120ml) vegetable oil (e.g., canola, sunflower, or vegetable oil)
• 1/4 tsp salt