In large mixer bowl cream together butter and shortening.
Gradually add sugar, creaming till light.
Add eggs, one at a time, and vanilla, beating well after each addition.
Stir together flour, nutmeg, soda, baking powder, and salt.
Add to creamed mixture alternately with buttermilk, beating after each addition.
Turn into greased and lightly floured 13x9x2-inch baking pan.
Bake at 350° till wooden pick inserted in center comes out clean, about 30 minutes.
Meanwhile, just before cake is removed from oven, prepare Toasted Meringue Topping.
Carefully and quickly spread over hot cake.
Sprinkle with coconut.
Bake at 350° till meringue is golden, about 5 minutes.
Store cake in refrigerator.
Toasted Meringue Topping: In small mixer bowl beat 2 egg whites and 1/2 teaspoon vanilla at medium speed of electric mixer till soft peaks form, about 2 minutes.
Gradually add cup packed brown sugar, beating at high speed till stiff, glossy peaks form, about 4 minutes.