Preheat your oven to 350°F (180°C).

In a skillet, melt ½ cup of unsalted butter over medium heat. Mix in 1 cup of dark brown sugar and 2 tablespoons of lemon juice until bubbling. Stir for about 2 minutes, then remove from heat.

Line the bottom of an 8-inch round cake pan with parchment paper. Arrange the tinned pineapple rings at the base of the pan. Pour the warm caramel mixture over the pineapple slices.

In a mixing bowl, whisk together 1 cup of buttermilk, ½ cup of vegetable oil, 2 large eggs, and 2 teaspoons of vanilla extract until smooth.

In a separate bowl, whisk together 1 ½ cups of all-purpose flour, 1 cup of sugar, 2 teaspoons of baking powder, ½ teaspoon of salt, ½ teaspoon of baking soda, and ½ teaspoon of ground nutmeg.

Gently fold the dry mixture into the wet ingredients until just combined. If desired, fold in ½ cup of sweetened shredded coconut.

Pour the cake batter over the caramelized pineapple in the cake pan. Bake for 30 to 35 minutes.

Allow the cake to cool in the pan for about 30 minutes. Run a knife around the edge and invert the cake onto a serving plate.

Garnish with fresh raspberries or any fruit and serve warm with ice cream or chilled.