Preheat your oven to 350 degrees. Grease a 9x9-inch baking pan with butter or nonstick spray, then line with parchment paper if you want easy removal. Set aside.

In a large bowl, whisk together the flour, ginger, cinnamon, cloves, nutmeg, baking soda, and salt. Make a well in the center of the dry ingredients.

In a separate small bowl or measuring cup, stir the hot water into the molasses until combined. Add the brown sugar, melted butter, egg, milk, and vanilla. Whisk until the mixture is smooth and uniform.

Pour the wet ingredients into the well in the dry ingredients. Use a rubber spatula to fold everything together until just combined. A few small streaks of flour are fine. Do not overmix or the cake will be dense.

Pour the batter into the prepared pan and spread it to the edges. Arrange the apple slices in overlapping rows or a simple fan pattern across the top of the batter. Press each slice in gently so it sits just below the surface. Sprinkle the top with the tablespoon of granulated sugar and the extra cinnamon.

Bake for 35 to 40 minutes. The cake is done when the center springs back lightly when pressed and a toothpick inserted in the middle comes out with just a few moist crumbs, not wet batter. The apple slices on top will look soft and caramelized at the edges.

Let the cake cool in the pan for at least 15 minutes before slicing. Serve warm or at room temperature with a dollop of lightly whipped cream alongside.