Lasagne with Chard, Spinach and Hazelnuts - SippitySup

Ingredients

• 2 tablespoons extra-virgin olive oil
• 1 Swiss chard (leaves and stems separated, leaves roughly chopped, stems finely sliced)
• kosher salt (as needed)
• ½ pound baby spinach
• water (as needed)
• freshly ground black pepper (as needed)
• 2 ounces fresh Italian parsley (leaves and stalks roughly chopped)
• 2 ounces fresh dill (leaves and stalks roughly chopped)
• 3 tablespoons unsalted butter
• 2 cups whole milk (gently warmed) plus a splash more if needed
• ¼ cup all-purpose flour
• 4 cups finely grated Parmesan cheese (divided)
• 1 cup finely grated Gruyere cheese
• cooking spray (as needed)
• 1 ½ cup good quality tomato sauce (divided)
• 12 sheets dried lasagne noodles (cooked until al dente and set aside in a single layer on a greased baking sheet)
• 2 ½ ounce chopped hazelnuts