Way to go grandson!!! But to answer your question, yes and no. If all-purpose is called for in the recipe and you use cake flour, the hydration may be off a bit, so add 2 T. more of cake flour due to the difference in the amount of gluten which soaks up hydration.

Some cakes, such as snack cakes and pound cakes, are supposed to be more substantial, so cake flour may not be the best choice. Cupcakes and muffins may actually get too tender if you use cake flour since they are made to consume out-of-hand and could fall apart easily.

Cake flour is best used in cakes with a high ratio of sugar to flour for a finer texture and greater volume.

-Grainlady

Thank you Grainlady,
The grandson's cake is a coffee cake, and it was wonderful. My granddaughter made a peanut butter cake, and the three layers seemed a little too thin. The recipe calls for a cup of peanut butter in the batter, so I guess the cake flour would not be the right choice. She used the ap flour, and the cake was delicious, (also first place, and, best over-all). They make the same recipe year after year, always with blue ribbon results!
Jan

Oh my, will you share recipes?

AustinÂs Coffee Cake

Austin has made this coffee cake as his baking entry at the Martinsville Fair, with Blue Ribbon results! Yeah, Austin!!
Austin always uses real butter, and he also uses the cardamom called for in the Streusel, but it can be omitted..

HereÂs the recipe:

Streusel:
 1 ½ cups graham cracker crumbs
 ¾ cup finely chopped walnuts
 ¾ cup firmly packed brown sugar
 1 tsp. cinnamon
 ¼ tsp. ground cardamom
 ½ cup melted butter (1 stick)

To make the Streusel topping::
Combine crumbs, nuts, cinnamon, brown sugar, cardamom, and melted butter, and set aside.

Cake:
 2 cups cake flour
 1 cup sugar
 2 ½ tsp. baking powder
 ½ tsp. salt
 ½ cup butter, room temperature (1 stick)
 2 eggs
 1 ½ tsp. vanilla
 1 cup milk

Cake:
Combine dry ingredients, add butter, eggs, vanilla and milk. Beat 2 minutes.
Pour half the batter into a greased and floured 9"springform pan. Layer half the streusel, then add the remaining batter and repeat the streusel layer.
Bake in a 350 degree oven, for 50 minutes.
This cake can be served warm or cold.

Peanut Butter Lovers Cake
2 cups flour
1 tsp. baking soda
½ tsp. salt
¾ cup butter, softened
2 cups sugar
5 eggs, separated
1 cup creamy peanut butter
1 cup buttermilk
1 tsp. vanilla extract
Combine the flour, baking soda, and salt in a bowl, set aside. Beat the butter in a mixer bowl at medium speed until light and fluffy. Add the sugar gradually, beating constantly until blended. Add the egg yolks, one at a time, mixing well after each addition. Beat in the peanut butter. Add the dry ingredients alternately with the buttermilk. Stir in the vanilla. Beat the egg whites in a small mixer bowl at high speed until stiff peaks form. Fold into the batter.
Pour into 3 greased and floured, 9-inch round cake pans. Bake at 350 degrees for 25 to 30 minutes, or until a wooden pick inserted in the center comes out clean. Cool in the pans for 10 minutes. Remove to a wire rack to cool completely. Frost with Peanut Butter Frosting, sprinkle with peanuts. (or coarsely chopped peanut butter cups, or chocolate)
Peanut Butter Frosting
¾ cup butter, softened
1 cup creamy peanut butter
4 ½ cups powdered sugar
1/3 cup milk
1 tsp. vanilla
Beat the butter in a mixer bowl at medium speed until light and fluffy. Beat in peanut butter. Add the powdered sugar, gradually, beating constantly until well blended. Add the milk and vanilla, mix well. Add additional milk 1 Tblsp. at a time until of the desired consistency.
Note: this is definitely too much batter for a 9 X 13" pan.