However, my pie recipe skips that unnecessary step. Instead, I just mix all the ingredients together with the exception of my lemon extract and cook until only slightly thickened. Before pouring ...

You could make the pastry case and lemon filling in advance then whip up ... mixture - the sauce should thicken immediately. Cook over a low heat for three minutes, stirring until thickened ...

Cook the mixture for another minute, then pour it into the flan case. FOR THE TOPPING: Whisk the egg whites until they stiffen. This should take 5-7 minutes. Add the remaining Stevia, keep whisking, ...