Heat milk on med-high until small bubbles appear at the edge. Pour scalded milk into flour mixture and cook until it thickens, 2-3 minutes.
In a Lg. Bowl: whisk together egg yolks and add 1 TBS custard mixture (still on stovetop). Blend in vanilla, butter and rum (or bourbon). Cook 2 minutes more. Remove the bowl from the heat, and let cool, stirring a couple times. Fold in 1 cup of coconut and pour into pie shell, smooth out evenly.
In a Lg bowl, whip egg whites until STIFF. Add 5 TBS Sugar & continue to whip for 2 minutes until its glossy and stiff are formed peaks when beater is removed. Spread meringue over custard on pie. Bake 10-15min. Or until meringue is lightly browned.
**CUT with a knife dipped in warm water for ea. slice.