Fresh Plum Cake

INGREDIENTS

• 1 ½ cups all-purpose flour (7 oz.)
• 1 tsp. baking powder
• ¼ tsp. salt
• ¾ tsp. pumpkin pie spice, divided
• 1 cup unsalted butter, room temperature (could use shortening)
• 1 cup sugar + 1 Tb.
• 2 extra-large eggs (or 2 large + 1 egg white)
• 6-8 plums