Spinach Frittata With Feta Cheese

Ingredients

• 2 tablespoons olive oil
• 1 small onion (finely chopped)
• ½ teaspoon salt
• 2 cloves garlic (finely chopped)
• 5 oz. baby spinach (5-6 cups or 150 grams)
• 8 large eggs
• ¼ cup chopped parsley (6-7 grams)
• ¼ cup chopped dill (6-7 grams)
• ½ teaspoon pepper
• Zest of 1/3 lemon (optional)
• ⅓ cup cream (e.g. heavy cream, cooking cream)
• ½ cup feta (crumbled, about 90 grams / 3 oz.)
• ⅔ cup grated cheddar cheese (90 grams / 3 oz.)
• 1 teaspoon butter (for greasing the pan)