FOR THE CRUST: Pre heat oven at 350 F . Place flour,confectioner's sugar,salt in a large bowl. Mix and then add in sliced butter and using your hand, incorporate the butter with the flour mixture. Add the olive oil intermittently until the crust is flaky. Place the crust into a 7 x 5 baking sheet and press hard into the baking pan, make sure to seal any cracks.Bake in a preheated oven until brown, around 20 minutes.

FOR THE FILLING : Meanwhile mix the granulated sugar,flour in a bowl.Set aside.In the other bowl, mix the lemon juice, orange juice and lemon zest, milk and eggs. Beat and then add into sugar mixture. Beat until there will be no more lumps. Pour mixture into the hot crust and bake for another 25 minutes - lower the oven temperature to 325 F. Bake until the filling is set. The filling will look bubbly but it will set once you remove it from the oven and while it is cooling. Let cool and and slice into match box size squares. Serve immediately or, refrigerate before serving. Store left over in an air tight container.