Set to 350°F (180°C) on convection mode. Line a sheet pan with parchment paper.

In a medium bowl, whisk together the eggs, milk, flour, salt, and pepper until smooth.

In a separate bowl, mix the cottage cheese, white cheese, and crumbled Bulgarian cheese until well combined.

Lay one sheet of phyllo in the baking dish and lightly brush with oil or spray. Repeat with a second sheet. Take a sheet of phyllo, crumple it loosely, and dip it into the egg mixture. Shake off excess and place in the dish. Repeat with 12 sheets, arranging them side by side to form a full, textured layer. Spread the cheese mixture evenly over the soaked phyllo layer. Place a sheet of phyllo over the cheese, brush with oil, and repeat with one final sheet. Transfer to the oven and bake for about 50 minutes, or until deeply golden and crisp.

Let cool for a few minutes before slicing into squares. This borek is best enjoyed fresh but can be stored in the fridge for up to a day.