1/2 cup (1 stick) unsalted butter, softened, plus extra for greasing the pan
1   7 - ounce tube of almond past (not marzipan), coarsely grated
2/3 cup confectioner's (powered) sugar, plus extra for garnish
2 large eggs
2 teaspoons pure almond extract
1 cup unbleached all-purpose flour
1 teaspoon baking powder
1/4 teaspoon baking soda
1/4 teaspoon salt
1/2 cup sour cream
1 pound ripe apricots, pitted and cut into quarters or sixths, depending on their size
1 tablespoon unsalted butter, melted
1 tablespoon turbinado sugar