1. Preheat oven to 350°. Beat butter at medium speed with an electric mixer until creamy; gradually add sugar, beating until light and fluffy. Add egg yolks, 1 at a time, beating until blended after each addition.2. Stir together flour and next 2 ingredients; add to butter mixture alternately with milk, beginning and ending with flour mixture. Beat at low speed just until blended. Stir in zest and juice.3. Beat egg whites in a large bowl at high speed until stiff peaks form. Gently stir one-third of egg whites into batter; fold in remaining egg whites. Fold in jam or strawberries Spoon batter into (with oil) and place cupcake paper in non stick muffin pan . Bake at 350° for 16 to 20 minutes or until a wooden pick inserted in center comes out clean. Cool in muffin pan 10 minutes; remove from pans and cool completely.place cool cupcake on tray, Spoon 1 cup Strawberry Frosting into a piping bag Pipe a ring of frosting around cup-cake layer just inside the top edge. Top the middle of t