I was in a similiar meyer lemon situation as heidipie below so last week I busted out the ol' 1953 Joy of Cooking to make a lemon meringue pie. It's a very good filling with a lush, creamy texture that I prefer over sometimes rubbery or goopy cornstarch-based lemon fillings. As you can see from the picture it's not firm-firm, but it holds its shape when you cut through it. You could fill a prebaked tart or pie shell with it and top with meringue.
Lemon Meringue Pie filling, Method III for a 7" pie
1/2 c butter
1 c sugar
rind and juice of 2 lemons
1 egg yolk
In the bowl of double boiler, combine & blend butter, sugar, and lemon juice and rind. Set the bowl over (but not in) simmering water. Stir until melted.
In another bowl, beat eggs and egg yolk. Add to double boiler mixture and cook, whisking every so often, until a thickened custard emerges. Test if it coats the back of a spoon and then cook a little further until it's pudding-like. Remove from heat and cool. Fill your prebaked, cooled pie shell and top with meringue.