Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan, or line the bottom with parchment paper.

In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt until well combined.

In a separate bowl, cream the softened butter until light and fluffy. Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Mix in the vanilla extract.

Gradually add the wet ingredients to the dry ingredients, alternating with the milk, mixing on low speed just until incorporated. Do not overmix.

Gently fold in the corn kernels. Pour the batter into the prepared cake pan and spread evenly.

Arrange the thin nectarine slices decoratively over the top of the batter. If using, sprinkle lightly with coarse sugar.

Bake for 35 to 40 minutes, or until a toothpick inserted into the center comes out clean. The top should be golden brown.

Let the cake cool in the pan for 15 minutes before inverting it onto a wire rack to cool completely.