For the Cake:
Preheat oven to 350 degrees . In a bowl, whisk the flour, baking powder and salt.
In an electric mixer fitted with the whisk attachment, beat the butter on high until creamy, 2 minutes. With the machine on, gradually add the sugar and beat, scraping the bowl, until fluffy, 8 minutes. Beat in the eggs one at a time, scraping the bowl. Beat in the vanilla. At low speed, add the flour mixture in three additions, alternating with the milk. At medium speed, mix until smooth. Transfer to parchment-lined 9-by-13-inch pan; bake for 40 minutes; invert and let cool on a rack.
For the Frosting:
In an electric mixer, beat the butter and salt at medium speed until creamy about 1 minute.
Sift in the confectioners' sugar, 1 cup at a time, mixing at low speed to incorporate (the mixture will be crumbly). Beat at medium speed for 1 minute, then increase to high speed and beat until smooth, 3 to 4 minutes. Beat in jam until smooth, 2 to 3 minutes.Gradually add the cream then beat until fluffy, 2 to 3 minutes.
For the Edible RIbbon:
For a convincing ribbon stand-in, heat 20 soft red fruity candies, such as Starburst, in the microwave on high at 5-second intervals, until soft. Knead into a ball, roll out between sheets of wax paper and cut into strips.
Halve the cake crosswise. Place one half on a platter. Spread with 1 cup Berrylicious Frosting. Top with the remaining cake half. Cover with the remaining frosting. Wrap with strips of candy, such as fruit leather (or try our edible ribbon candy trick). Top with fresh berries.