Preheat the oven to 350°F (175°C) and grease a muffin tin with butter or non-stick spray.

In a medium bowl, whisk together the flour, baking powder, and salt.

In a large bowl, cream together the butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition, and stir in the vanilla extract.

Gradually fold in the flour mixture into the wet ingredients, alternating with the milk.

In a saucepan, combine the brown sugar, whipping cream, butter, and salt, stirring continuously over medium heat until smooth.

Fill muffin tins halfway with cake batter, then drizzle warm caramel over each.

Bake for 18-20 minutes, or until golden brown; check with a toothpick.

Cool for 5 minutes, then sprinkle with flaky sea salt before serving.