This gratin uses fresh zucchini and onion for a soft texture and mild flavor. Traditional recipes often use pepper jack cheese and heavy cream, which can be high in histamine. This version swaps in low histamine dairy alternatives and safe seasonings to create a creamy, golden top without triggering symptoms. It’s easy to prepare and bakes into a bubbling, satisfying dish that pairs beautifully with almost any protein.

Ingredients Needed:

4 cups raw zucchini: sliced thinly, fresh (not pre-cut or stored).
1 small onion: thinly sliced (optional, can omit if sensitive).
¼ teaspoon sea salt: or to taste.
Pinch white pepper (optional): avoid black pepper.
1½ cups low histamine shredded cheese: use young goat cheese, fresh mozzarella, or omit for dairy-free.
2 tablespoons olive oil or ghee: instead of butter.
½ teaspoon garlic powder (optional): or use garlic-infused olive oil if tolerated.
½ cup unsweetened rice or oat milk: as a low histamine alternative to cream.
¼ teaspoon xanthan gum or tapioca starch: helps thicken.

How To Make Low Histamine Zucchini Gratin:

Prep the Oven and Dish:
Preheat your oven to 375°F (190°C). Grease a 9×9-inch baking dish with olive oil or ghee.

Layer the Zucchini and Onion:
Create 3 layers in the dish: for each layer, overlap zucchini and onion slices, sprinkle lightly with salt and pepper (if using), and add ½ cup shredded cheese (or skip for dairy-free).

Make the Sauce:
In a small saucepan or microwave-safe bowl, combine olive oil or ghee, garlic powder (if using), rice/oat milk, and xanthan gum. Heat just until warm and whisk until smooth and slightly thickened.

Assemble and Bake:
Gently pour the sauce evenly over the layered zucchini. Bake for 45–46 minutes until bubbly and golden on top.

Serve Warm:
Let rest for 5 minutes before serving for easier slicing.

Recipe Tips:

Use fresh zucchini only—pre-cut or stored slices can build histamine.
Choose a young, mild cheese like fresh mozzarella or omit for safest results.
For dairy-free, use only plant milk and skip cheese entirely.
Omit onion or garlic powder if they’re personal triggers.

How to Store & Reheat:

Room Temperature: Serve immediately; avoid leaving out longer than 1 hour.
Fridge: Store in a sealed container for up to 2 days.
Freezer: Not recommended—reheating can increase histamine.

Nutrition Facts (approx. per serving, using dairy-free options):

Calories: 110
Sodium: 180 mg
Protein: 3 g
Fat: 8 g
Carbs: 8 g
Fibre: 1 g
Sugar: 3 g

FAQs:

Is zucchini low histamine?
Yes, fresh zucchini is low histamine and gentle on digestion.

Can I use cheese in a low histamine diet?
Only use fresh, non-aged cheeses like mozzarella or young goat cheese. Aged cheeses like pepper jack are high histamine and should be avoided.

Is heavy cream high in histamine?
Yes, heavy cream is often high in histamine. Use plant-based milk like rice or oat milk instead.

Can I make this gratin dairy-free?
Absolutely. Use olive oil and plant-based milk, and skip the cheese or use a histamine-safe vegan cheese if tolerated.

What can I use instead of xanthan gum?
You can use a small amount of tapioca starch or arrowroot powder to help thicken the sauce.

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