upside down plum and olive oil cake

Ingredients

• 6-8 - medium plums, pitted and sliced
• 2 cups all-purpose flour
• 1 3/4 cups brown sugar
• 1 1/2 teaspoons kosher salt
• 1/2 teaspoon baking soda
• 1/2 teaspoon baking powder
• 1 1/3 cups best quality olive oil
• 1 1/4 cups whole milk
• 3 - large eggs
• 1 teaspoon almond extract
• 1 tablespoon lemon zest, grated
• 2 tablespoons lemon juice
• 6 tablespoons champagne (or sparkling cider or club soda or similar)
• - lightly sweetened whipped cream, for serving