Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour your cake pan or line it with parchment paper.
Prepare the Cake Batter: In a mixing bowl, cream the softened butter and granulated sugar together using a whisk or electric mixer until the mixture is light and fluffy. Add the eggs one at a time, beating well after each addition. In another bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the butter mixture, alternating with the milk. Stir in the vanilla extract. Mix until the batter is smooth and fully combined.
Prepare the Red Currant Topping: Gently rinse and remove the stems from the red currants. Place them in a small bowl and sprinkle with sugar. For a thicker topping, mix the cornstarch with a small amount of water and stir into the currants to help bind the juice.
Assemble the Cake: Pour the cake batter into the prepared pan and smooth the top. Evenly distribute the sugared red currants over the top of the batter, gently pressing them in so they don't slide off.
Bake: Bake the cake for about 40-45 minutes, or until a toothpick inserted into the center of the cake comes out clean. If the top of the cake starts to brown too quickly, cover it loosely with foil.
Cool and Serve: Allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely. Once cooled, slice and serve.
