Blueberry-Lavender Polenta Cake

Ingredients

• 3/4 cup polenta
• 1 1/3 cups sugar, plus more for cake pan
• 1 cup all-purpose flour
• 2 teaspoons baking powder
• 1 teaspoon salt
• 1 tablespoon lavender, crushed
• 5 eggs, at room temperature
• 2 egg yolks
• 1/2 cup olive oil
• 1 teaspoon vanilla extract or seeds from 1/2 split vanilla bean
• 1/2 cup butter, at room temperature
• 2 cups fresh or frozen blueberries, tossed in 2 tablespoons flour
• Whipped cream, for serving (optional)
• Blueberry compote, for serving (optional)