Don't have the EDC book here - not sure of the recipe. Have you cut the pie up? You can try to lift the meringue off and put it on silicon paper and then scrape out the filling and place some butter and cornflour - maybe a dessertspoon of each (depending on how runny) into TM bowl with small amount of the filling and mix and heat it up to 80oC for a couple of minutes, before adding the rest of the filling and cooking it for about 5 minutes on 80oC and then placing back into the flan and placing top back on.
We may be talking at cross purposes?