Orange Polenta Cake with Vanilla-Scented Plums and Blackberries and Buttermilk Ice Cream

INGREDIENTS

• 2 teaspoons (packed) finely grated orange peel
• 1/2 teaspoon salt
• 4 large eggs, room temperature
• 3/4 cup medium-fine polenta or organic cornmeal (such as Bob's Red Mill)
• 1 teaspoon vanilla extract
• 1 cup plus 2 tablespoons sugar
• 1 cup (2 sticks) unsalted butter, room temperature
• 1/2 cup whole-milk plain yogurt
• 1 1/4 cups all purpose flour
• 1 1/2 teaspoons baking powder