Fish and potato gratin | Dom Cooks

Ingredients

• 4 russet potatoes, peeled and diced
• 2 small parsnips, peeled and diced
• 1 cup 2% milk
• 0.25 cup unsalted butter
• 0.25 tsp ground nutmeg
• 1 tsp kosher salt
• Freshly ground pepper, to taste
• 1 small yellow onion, finely chopped
• 1 cup Portuguese or Spanish chorizo (I use the Delisa brand), cut into small 1-cm cubes
• 1 clove garlic, finely grated
• 1 cup 35% cream
• 0.5 tsp cornstarch
• 3 tbsp finely chopped flat-leaf parsley
• 2 tbsp finely chopped tarragon (optional)
• 2 handfuls baby spinach
• Zest of one lemon
• Juice of half a lemon
• 1.12 lbs Icelandic cod fillet, cut into 1-inch (2.5 cm) pieces
• 1 cup panko breadcrumbs (or homemade breadcrumbs made with fresh bread)
• 0.5 cup grated Parmesan cheese
• 1 tbs extra virgin olive oil