Vegetable lasagna with zucchini, asparagus and spinach

Ingredients:

Vegetable lasagna

• 450 g lasagna sheets
• 3 tbsp. l. olive oil
• 1 medium onion, finely chopped
• 1 medium carrot, finely chopped
• 1 medium zucchini, finely chopped
• 1 medium Mexican squash, finely chopped
• 8 asparagus spears, cut into skewers
• 2 cups tomato sauce, recipe included
• 1.5 cups canned white beans, rinsed and drained
• 2 packages (280 g each) frozen chopped spinach, thawed and squeezed dry
• 3 tbsp. coarsely grated mozzarella
• 1/2 tbsp. grated parmesan
• 3 tbsp (45 g) butter, divided into 2 parts

Tomato sauce

• 2 cans (910 g each) of chopped tomatoes
• 1/2 cup olive oil
• 1 small onion, chopped
• 2 cloves garlic, chopped
• 1 stalk celery, chopped
• 1 carrot, chopped
• 2 dried bay leaves
• 4 tbsp (60 g) butter, optional

Preparation:

1. Preheat oven to 190°C.
2. Pour olive oil into a sauté pan over medium heat. When it's almost smoking, add the onion and cook until softened (about 5 minutes). Add the carrots and sauté for 3 minutes.
   
   Add the zucchini and squash and cook for 5 minutes. Add the asparagus and cook for 2 minutes. Remove from heat when all vegetables are cooked through but still crisp. Let cool.
3. Using a 6-inch (15-cm) metal baking ring, cut 18 circles from lasagna sheets. Coat the bottom of each of 6 6-inch (15-cm) gratin dishes with 1 teaspoon of tomato sauce. Then place the pasta circles on top. Rinse the beans with water, season with salt and pepper. Divide the beans among the ramekins.
4. Then place a portion of spinach in each ramekin. Place a second layer of pasta on top and press gently. Divide the sautéed vegetables among the ramekins. Top with 1 tablespoon of tomato sauce. Place a third layer of pasta in each ramekin and cover with 1 tablespoon of tomato sauce.
5. Sprinkle the contents of the molds with mozzarella and Parmesan cheese, and top with 1/2 tbsp (30 g) of butter. Line a baking sheet with foil and place the molds on it. Bake in the oven for 20 minutes or until the crust is browned and bubbly.

6. Tomato sauce

   
   In a large heavy-bottomed saucepan, heat the olive oil over medium-high heat. Add the onion and garlic. Sauté until soft and translucent, 5-10 minutes. Add the celery and carrots, season with salt and pepper. Sauté until all the vegetables are soft, about 5-10 minutes. Add the tomatoes and bay leaves. Simmer, uncovered, for 1 hour or until thickened. Remove the bay leaves and season with more salt and pepper. If the sauce is still too tart, add more butter (1 tablespoon at a time) to soften the flavor.
   
   Place 1/2 of the tomato sauce in a food processor. Puree until smooth. Repeat with the remaining tomato sauce.
   
   If you won't be using all the sauce right away, let it cool completely and pour 1-2 cup portions into freezer-safe plastic bags. It will keep frozen for up to 6 months..