In a saucepan, combine egg yolks, brown sugar and flour. Mix in the cream. Cook, stirring constantly, until thickened. Remove from heat and stir in butter. Pour into pre-baked pie shell.
In a large glass or metal mixing bowl, beat egg whites until foamy. Gradually add white sugar, continuing to beat until stiff peaks form. Spread meringue over pie, covering completely.
Bake in preheated oven for 5 to 10 minutes, or until meringue starts to brown.
