Preheat oven to 350°F (175°C). Grease a 9-inch springform pan.

In a medium bowl, whisk together flour, baking soda, salt, cinnamon, and nutmeg.

In a large bowl, cream butter and sugar until fluffy. Add eggs one at a time, mixing well after each addition. Stir in vanilla.

Gradually add dry ingredients to wet ingredients, mixing until combined. Fold in diced apples and nuts (if using).

Pour batter into the prepared pan and bake for 35-40 minutes.

Meanwhile, prepare caramel topping. In a small saucepan over medium heat, combine brown sugar, half-and-half, and butter. Stir until smooth and creamy.

After the initial bake, remove the cake from the oven. Drizzle caramel over the top. Return to the oven for an additional 10-15 minutes or until a toothpick inserted into the center comes out clean.

Cool for 15 minutes before serving.