The almonds add a welcome fresh flavor to this roll and the airy berry filling gives the whole a fluffy lightness not found in the more usual jelly roll. However, the dessert does slither a bit when served; be sure to have a sharp-edged, broad-based cake knife handy.
Line a jelly-roil pan with waxed paper; oil the paper. Separate the eggs. With a heavy whisk, beat the yolks with the sugar until the mixture ribbons. Beat in the ground almonds and the baking powder. Beat the egg whites until stiff and gently fold into the almond mixture. Spread the batter out on the oiled paper. Bake at 350 degrees F for 15 to 20 minutes. Cool in pan, then cover (the cake still in the pan) with a damp cloth and chill. Just before serving, whip the cream and fold in the mashed berries. Dust the top of the cake with confectioners’ sugar and turn it out onto a towel. Remove the waxed paper. Spread the surface of the cake with the strawberry whipped cream. Roll the cake and place on a platter. Dust with confectioners’ sugar and garnish with fresh berries, if available.