Mini Chocolate Cakes

• 3/4 cup all purpose flour
• 1/4 teaspoon baking soda
• 1/4 teaspoon baking powder
• 1/4 teaspoon salt
• 1/2 cup boiling water
• 2 ounces dark chocolate chopped fine
• 1/4 cup cocoa powder
• 1 teaspoon instant coffee optional
• 3 ounces unsalted butter room temperature
• 1/2 cup brown sugar
• 2 eggs room temperature
• 1/4 cup sour cream
• 1 teaspoon vanilla extract
• Salted Caramel Sauce or Candy Cap Caramel Sauce
• Sea salt to serve