1. For the pastry, blend the butter cubes and flour into small crumbs quickly so the butter stays cold. In a separate small bowl, combine egg yolks with 2 tsbs. water, then blend into flour crumbs until pastry reached right consistency -- this may require a few more drope of water blended into the pastry.
2. Roll out cold pastry on floured surfce and place on to pie tin. Then refridgerate foir 30 minutes.
3. Prick the bottom of pastry pie bottom and heat oven to 200c/180c fan /gas 6 nad blind bake for 15 minutes (my grandmother did not use parchemnt paper or beans to keep the pastry from rising.she just pricked the pastry several times right before putting it in the oven.).
4. For the filling, slowly heat guava paste, 2 tablespoons of water, sugar and lime juice for until just blended. Remove from heat.
5. Add butter and beaten whole egg and egg yolks to pan. Heat at medium, stirring vigorously for a few minutes until blended and then set the filling aside in the refridgerator.
6. For the meringue, whisk egg whites into stiff peaks, slowly add sugar, whisking as you add a bit at a time. Finally whisk in the corn flour until you have thick glossy peaks.
7. Pour the filling in the pastry case, followed by the meringue. Bake for 18 -20 minutes until the meringue is crisp and slightly coloured. Let the pie sit for at least an hour before serving.