Меня заинтересовала разница между Apple sauce and Apple butter. Как я и представляла - butter это концентрививанный соус и ещё со специями - корица, мускатный орех и можно взять любые на вкус. Соус - пюре из яблок. Яблоки пекутся в духовке или тушатся в толстостенной кастрюле. Если дальше упаривать пюре, то получится "butter".
А на основе этого "масла" пекутся пироги. Да и на соусе тоже можно делать маффины, пироги и др. выпечку.

Рецепт и фото взяты с интернета

APPLE BUTTER CAKE

• 1/2 c. shortening (растительное или сливочное масло)
• 1 c. sugar
• 3 eggs
• 1 c. apple butter
• 2 1/2 c. sifted cake flour
• 1 tbsp. baking powder
• 1/2 tsp. baking soda
• 1/2 tsp. salt
• 1/2 tsp. cinnamon
• 1/4 tsp. nutmeg
• 1 c. sour milk (кефир или йогурт)
• 1/2 c. apple butter - to cover the cake

с - сокращенно "cup".
1 cup (чашка) = 250 мл

Cream together shortening and sugar. Beat in eggs, one at a time; beat until light and fluffy. Stir in 1 cup apple butter.

Sift together flour, baking powder, baking soda, salt, cinnamon and nutmeg. Add dry ingredients to creamed mixture, alternately with sour milk. (To make sour milk: Measure 1 tbsp. vinegar or lemon juice and add milk to make 1 cup.)

Turn into greased and lightly floured 9 inch cake pans. Bake at 350 degrees for 30-35 minutes. Cool 10 minutes. Remove pans and cool thoroughly.

Spread bottom layer of cooled cake with 1/4 cup apple butter. Top with 1 cup fluffy frosting, spreading evenly to cover apple butter. Cover with top cake layer.

Frost sides and top of cake with remaining fluffy frosting. Swirl remaining 1/4 cup apple butter onto frosted top to give a marbled effect.

FLUFFY FROSTING
 

• 2 egg whites
• 1 1/2 c. sugar
• 1/4 tsp. cream of tartar
• 1/2 c. cold water
• dash salt
• 1 tsp. vanilla

Place egg whites, sugar, cream of tartar, water and salt in top of double boiler. Do not heat. Beat 1 minute with electric beater. Place over boiling water and cook, beating constantly until frosting forms stiff peaks, about 7 minutes. Remove top and from boiling water and add vanilla. Beat until of spreading consistency, about 2 minutes more.