Preheat oven to 180°C. Add olive oil to the bottom of a tart dish or round cake tin.
Mix the 1/4 cup olive oil with crushed garlic, oregano, salt and pepper.
Fan-fold each filo sheet (double up sheets if thin, like baklava pastry). Twist the first into a rose shape and spread the others around it, each starting where the last finished. TIP: cover the unused pastry with a tea towel so it does not dry out.
Once the tart case is filled, brush the olive oil mixture all over and into the sides so it is fully coated. Bake for 13-15 minutes until golden.
While it bakes, grate the cheese and whisk the custard ingredients together.
Sprinkle the cheese over the par-baked pastry, pour the custard over, top with fresh rosemary, and bake a further 30-35 minutes on a middle-to-low shelf.
