Preheat your oven to 375°F (190°C) and lightly grease a 9x13-inch baking pan with some of the melted butter.

Place the grated summer squash in a colander, toss with 1 teaspoon of salt, and let it sit for 15 minutes to draw out excess moisture.

Squeeze the squash firmly with your hands or press it through a clean kitchen towel to remove as much liquid as possible.

In a medium bowl, combine the squeezed summer squash, crumbled feta, cottage cheese, beaten eggs, chopped dill, and black pepper, stirring until the mixture is evenly blended.

Lay out the phyllo sheets on a clean surface and cover them with a damp towel to prevent them from drying out.

Place one sheet of phyllo in the prepared baking pan, brush lightly with melted butter, and repeat until you have layered 6 sheets for the bottom crust.

Spread the summer squash and cheese mixture evenly over the bottom layer of phyllo dough, smoothing it out to the edges with a spatula.

Layer the remaining 6 sheets of phyllo dough on top of the filling, brushing each sheet with melted butter as you stack them.

Score the top layers of the pie into squares using a sharp knife, taking care not to cut all the way through to the bottom.

Bake for 45 to 50 minutes, or until the top pastry turns deeply golden brown and crispy.

Let the pie rest for 10 minutes before slicing fully and serving warm with a dollop of Greek yogurt.