Preheat Oven: Preheat oven to 200ºC (400ºF). Grease a 9-inch × 13-inch dish with olive oil.
Vegetable Mixture
Sauté Onion & Garlic: In a large skillet, cook onion until translucent. Add the garlic and cook for a further 1 minute.
Add Carrot & Cauliflower: Cook for 4 minutes until carrot and cauliflower start to soften.
Cook Zucchini: Add zucchini and cook for a further 2 minutes until just soft, adding more oil if needed.
Mix in Peas & Spinach: Add the frozen peas and spinach, cook until spinach wilts, about 2-3 minutes. Season with salt and pepper to taste.
Set Aside Vegetables: Turn off the heat and keep veggies in the skillet while you make the white sauce.
Dairy Free White Sauce
Heat Oil Skillet: Place a large skillet over medium heat on the stovetop. Pour in the olive oil and warm over medium heat for 30 seconds to 1 minute until it’s heated through and warm/hot to the touch, don’t let it bubble.
Whisk in Flour: Turn the heat to medium-high, sprinkle in the flour and whisk through for 1 minute.
Add Milk: Gradually whisk in milk, cooking over medium heat, whisking gently until sauce thickens, without boiling or simmering.
Season: Once sauce has thickened, whisk through the nutmeg and salt and pepper to taste.
Add Cheese: Whisk through 2 cups of the cheese until combined and melted. Turn off the heat.
Assemble Lasagna
First Layer: Place 4 lasagna sheets in the baking dish.
Add Vegetables: Spoon over half of the vegetable mix.
Add Sauce: Pour over one-third of the white sauce.
Repeat Layers: Another 4 sheets, remaining vegetables and the second third of the sauce.
Top Layer: Last 4 sheets, remaining white sauce and sprinkle over the last 1 cup of cheese.
Bake: Bake for 40-45 minutes until golden and bubbling around the edges.
Rest: Remove from the oven and let it sit for 5-10 minutes.
Garnish & Enjoy: Garnish with chopped parsley, serve and enjoy!
Notes
Store: Wrap leftover lasagna in the baking dish or individual portions in cling film and foil; refrigerate for 2-3 days.
Reheat: Reheat refrigerated lasagna in a preheated oven at 350ºF (175ºC) until warmed through.
Freezing Uncooked: Assemble uncooked lasagna in a freezer-safe dish, cover, label, and freeze for 2-3 months. Thaw overnight and bake as instructed.
Freezing Cooked: Cool completely, wrap whole or in portions, label, and freeze for 2-3 months. Thaw overnight and reheat at 350ºF (175ºC).