Nonstick cooking spray, for the sheet pan
1 1/4 cups all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon fine sea salt
3.5 ounces almond paste, broken into small bits
1 cup granulated sugar
1/4 cup honey
2 sticks (1 cup) unsalted butter, at room temperature
6 large eggs
1 1/2 batches Royal Icing, recipe follows
Violet and green gel food coloring (or your preferred colors), as needed
1/3 cup seedless blackberry jam
1 cup white chocolate chips
4 cups confectioners' sugar
1/3 cup hot water, plus up to 1/4 cup more if needed
1/4 cup light corn syrup
4 cups sifted confectioners' sugar
3 tablespoons meringue powder
5 to 6 tablespoons warm water