Preheat oven to 400°F. Slice zucchini into approximately 1/4 inch round slices. Dice half of a yellow onion. Butter a medium sized casserole dish.

Line the pan with the zucchini slices, stopping halfway to add in the onion. Continue to layer until you've added all of the zucchini.

In a saucepan, melt butter over medium heat. Once melted, add minced garlic until it's cooked and aromatic, approx. 2 minutes. Mix in almond milk, heavy cream, and almond flour. Whisk until combined and it begins to thicken.

Stir in 1 cup of shredded cheddar cheese and stir until melted through. Salt and pepper to taste.

Pour cheese mixture over the vegetables in the casserole dish, and top with remaining ½ cup of cheddar.

Cover with aluminum foil and bake for 30 minutes. Then remove foil, and continue to bake uncovered for 20-25 minutes until zucchini are tender and the cheese on top has browned.