Preheat oven to 180 degrees C. 

Boil a pan of water and blanch spinach for 30 seconds. Remove from the water and drain under a weight or squeeze the water out. 

Mix the cheese with the chilli flakes. Season with black pepper. When the spinach is cool, add this too. If your mixture looks a bit sloppy, drain off whatever liquid you can and add a handful of breadcrumbs. 

Melt butter. 

At the end of a large flat surface, lay out the first sheet of yufka. Baste well with melted butter. Arrange the next sheet of yufka so that there is at least a hand width's overlap. Baste this next sheet of yufka with butter and repeat until you have used the yufka. 

Lay out the filling in a sausage shape a couple of centimetres from the bottom of the yufka. Then, gently roll the yufka over the filling until you have a sausage enclosed in pastry. Roll around a few more times (I usually find 3 is enough and more makes it difficult to handle). Trim off excess pastry. If you are anything like me and always break the pastry, use these trimmings to patch up any breakages. 

Take a pie tin (I use one with a removable base) and, starting at the edge, start to lay the pastry sausage round the outside of the tin and then spiral it into the middle of the tin. 

Beat the eggs and baste the top of the börek. 

Bake for 25-30 minutes, finishing the top off under the grill to get a nice golden finish if necessary.