Prepare the Eggplant: Preheat your oven to 375°F (190°C).

Grease a rimmed baking sheet with a small amount of coconut oil.

Peel the eggplants completely.

Using a mandolin or sharp knife, slice the eggplants lengthwise into 0. 25-inch (0.6 cm) thick slices.

Arrange the slices in a single layer on the baking sheet.

Sprinkle generously with sea salt and pepper.

Bake for 10 to 12 minutes to soften.

Remove from the oven and set aside.

Prepare the Baking Dish: Grease a 9 x 13-inch (23 x 33 cm) baking dish with coconut oil.

Adjust your oven rack to the middle position and increase the oven temperature to 425°F (220°C).

Start the Sauce: In a large saucepan, combine the chopped onion, 1.0 tsp of coconut oil, and a pinch of sea salt.

Cover and cook over medium-low heat until the onions are softened, approximately 8 to 10 minutes.

Stir in the minced garlic and cook for 30 seconds until fragrant.

Simmer and Thicken: Pour in 2.75 cups (22 fl oz / 650 ml) of the coconut milk, add the bay leaves, and the 0.5 tsp of nutmeg.

Bring the mixture to a simmer.

In a separate small bowl, whisk the 2.0 tbsp of arrowroot/tapioca flour with the remaining 0.25 cup (2 fl oz / 60 ml) of coconut milk to create a slurry.

Whisk this slurry into the simmering pot.

Continue to simmer, whisking constantly, until the sauce has slightly thickened.

Finish the Filling: Remove the pot from the heat and discard the bay leaves.

Stir in the dried spinach and 0.5 cup (approx. 2.0 oz / 57 g) of the shredded cheese.

Season with sea salt and pepper to taste.

Cover and set aside.

Assemble: Spread a thin layer of the sauce on the bottom of the prepared baking dish. Lay a single layer of the roasted eggplant slices on top of the sauce.

Sprinkle the eggplant with a portion of the remaining cheese, then cover with a layer of sauce.

Repeat these layers until all eggplant slices are used.

Finish by topping the lasagna with the remaining cheese.

Bake: Grease a sheet of aluminum foil with coconut oil.

Cover the baking dish tightly with the foil (oil side down).

Bake until the sauce is bubbling around the edges, approximately 20 minutes.

Broil: Remove the lasagna from the oven.

Adjust the oven rack to a position about 6 inches from the top heating element and turn on the broiler.

Remove the foil from the dish. Broil for about 5 minutes, or until the cheese is spotty brown and bubbly. Allow the lasagna to cool slightly before slicing and serving.

Squeeze the Spinach "Bone Dry": This is the most critical step. Frozen spinach holds a massive amount of water.

After thawing, wrap it in a clean kitchen towel or cheesecloth and wring it out until absolutely no more liquid comes out. If you skip this, your white sauce will turn into a watery soup at the bottom of the dish.

Don't Skip the Eggplant Roast: Roasting the eggplant slices (Step 1) isn't just about cooking them; it is about dehydrating them. Eggplants act like sponges. By pre-roasting them, you remove excess moisture that would otherwise seep out during the final bake. If they still look moist after 12 minutes, give them another 3 to 5 minutes.

Let It Rest: Unlike traditional flour-pasta lasagna which absorbs liquid as it cools, grain-free lasagna needs time to "set."

Let the dish rest on the counter for at least 15 to 20 minutes after taking it out of the oven. This allows the coconut milk sauce and arrowroot to firm up, making it much easier to cut nice, clean squares.

Neutralizing the Coconut Flavor: If you are worried about the sauce tasting too much like coconut, rely on the nutmeg and bay leaves—they are classic béchamel seasonings that mask sweetness. You can also add a pinch of nutritional yeast or a splash of lemon juice to the sauce to boost the savory, cheesy profile.

The Arrowroot Slurry: When adding your thickener (arrowroot or tapioca), make sure the liquid in the pot is simmering gently, not boiling violently. High heat can sometimes break the bond of arrowroot flour, causing the sauce to thin out again.

Whisk continuously and remove from heat as soon as it coats the back of a spoon.

Make It Meaty (Optional): If you have meat-eaters at the table, this recipe adapts easily. You can brown 1.0 lb (450 g) of grass-fed ground beef or Italian sausage with the onions in Step 2 before adding the coconut milk.