In a large skillet, melt 1 tablespoon of butter over medium-low heat. Add the thinly sliced yellow onions, cooking uncovered for 30–40 minutes, stirring regularly to caramelize.

While the onions are caramelizing, place 2 cups of small-curd cottage cheese in a fine-mesh strainer over a bowl to drain for at least 20 minutes.

Preheat your oven to 375°F (190°C) and grease a 9-inch pie dish.

In a blender, combine the drained cottage cheese, 3 large eggs, and 1 tablespoon of cornstarch. Blend until smooth and frothy.

Pour the blended custard into a mixing bowl. Stir in 1 teaspoon of fresh thyme, ½ teaspoon of salt, and ¼ teaspoon of black pepper. Fold in the caramelized onions and ¾ cup of shredded Gruyère cheese.

Pour the mixture into the greased pie dish and top with the remaining ¼ cup of Gruyère cheese. Bake for 35–40 minutes until golden.

Cool the bake for 10–15 minutes on a wire rack before slicing.