In a saucepan, heat honey until thin enough to brush over cake. Beat together mascarpone cheese, whipping cream, and 1 tablespoon of the honey until light and fluffy. Fold in lemon juice and rosemary. Slice the cake horizontally in half. Brush tops of layers with the honey. Spread bottom layer with filling. Top with second layer. Serve immediately or cover and chill up to 2 hours. Makes 10 to 12 servings.