Preheat the oven to 180°C using top and bottom heat (no fan).
Melt the butter and set it aside.
In a large bowl, beat all the eggs until the mixture is smooth and uniform.
Add the yogurt to the eggs and beat again until well combined. Crumble the cheese into small pieces and mix it in.
Grease a large baking pan with a little melted butter. Place two sheets of filo pastry in the pan. Drizzle about two spoonfuls of melted butter over the filo and spread evenly. Then add some of the egg-cheese mixture and spread it out.
Repeat the layering: two sheets of filo, melted butter, and egg-cheese mixture—until all the filo sheets are used. Make sure to reserve the last two sheets for the top, and use up all the filling before placing them.
Once all the layers are done, carefully score the banitsa with a knife into roughly 3x3 squares.
Pour the remaining melted butter evenly over the top. Add a bit of milk to the bowl that had the egg-cheese mixture, swirl it around to collect the leftovers, and pour that gently over the banitsa. Spread it evenly and carefully.
Place the banitsa in the middle of the preheated oven.
Bake for 30–40 minutes, or until golden and set. When ready, remove it from the oven and immediately cover with a clean cloth. Let it rest for at least 5 minutes.
Cut into moderately sized pieces and serve. It pairs perfectly with a side of yogurt!