Strawberry Upside-Down Cake

INGREDIENTS

• 1 1/2 cups self-rising flour
• 1/2 teaspoon salt
• 1/2 cup sugar
• 2 tablespoons butter, softened
• 1/2 cup strawberry nectar
• 8 strawberries, tops removed
• 4 tablespoons mascarpone, room temperature
• 2 large eggs
• 1/4 teaspoon baking soda
• 1/2 cup buttermilk
• 1 teaspoons vanilla extract
• 1/4 cup brown sugar
• 1/4 cup sugar, for ramekins
• Cooking spray, for ramekins
• Powdered sugar, to garnish