| 1 | Combine sugar, flour, cocoa and salt in medium saucepan; stir in milk. |
| 2 | Cook over medium heat, stirring constantly until mixture boils; remove from heat. |
| 3 | Stir half of the mixture into beaten egg yolks; return mixture to sauce pan. |
| 4 | Continue cooking and stirring over medium heat until mixture boils; boil and stir for 1 minute. |
| 5 | Remove from heat and stir in butter and vanilla. |
| 6 | Cool for 10 minutes, pour into pie shell. |
| 7 | Heat oven to 350°F. |
| 8 | Meanwhile, prepare meringue topping: in a small mixer bowl, beat egg whites and cream of tartar until foamy. |
| 9 | Gradually add sugar and beat until stiff peaks form. |
| 10 | Spread this on warm pie filling, carefully sealing to the edges of crust. |
| 11 | Bake 5 to 8 minutes, or just until meringue is lightly browned. |
| 12 | Cool to room temperature; chill for several hours. |
| 13 | Refrigerate leftovers |
