Preheat your oven to 350°F or 175°C (350°F).
In a small skillet, cook the chopped onion in hot olive oil over medium heat until tender and fragrant, stirring occasionally.
Set aside to cool slightly.
In a large bowl, combine the lightly beaten eggs, crumbled feta cheese, cottage cheese, dill, and salt.
Whisk until well-blended.
Stir in the cooled onion, thoroughly drained spinach, cooked brown rice, and lemon juice until everything is evenly incorporated.
Arrange six 8- to 10-ounce ramekins or custard cups in a 15x10x1-inch baking pan. Carefully divide the spinach and rice mixture among the ramekins.
Bake, uncovered, for 25 to 30 minutes, or until a knife inserted near the center of a bake comes out clean.
Let cool for a few minutes before serving. If desired, garnish with fresh lemon peel strips.
