In a large skillet over medium heat, melt 4 tablespoons of unsalted butter and 1 cup of brown sugar together until bubbly and fully combined, stirring regularly for about 2-3 minutes. Pour into a greased 9-inch round cake pan.

Carefully slice 6-8 fresh apricots in half, remove the pits, and place them cut-side up over the warm caramel in the cake pan.

In a large mixing bowl, cream together 1/2 cup of unsalted butter and 3/4 cup of brown sugar using an electric mixer on medium speed until light and fluffy. Gradually add in 2 large eggs, one at a time, followed by 1 teaspoon of vanilla extract until smooth.

In another bowl, whisk together 1 ½ cups of all-purpose flour, 2 teaspoons of baking powder, and a pinch of salt. Gradually add this dry mixture to the creamed butter and sugar mixture, mixing on low speed just until combined.

Gently pour the cake batter over the arranged apricots and caramel in the pan and bake in a preheated oven at 350°F (175°C) for 35 to 40 minutes.

Remove from the oven and let it cool in the pan for about 10 minutes. Run a knife around the edges to loosen, then invert onto a serving plate.

Slice while warm and serve with vanilla ice cream or whipped cream.