Preheat your oven to 325 °F (around 163 °C). Grease a 13×9‑inch (or 9×13) baking pan.

In a large bowl, combine the flour, granulated sugar, baking powder, baking soda, salt, cinnamon and nutmeg.

Add the oil, pumpkin puree and eggs to those dry ingredients. Use a whisk or an electric mixer on low just until everything is blended.

Pour the batter into the prepared pan and bake at 325 °F for about 30 minutes (or until a toothpick inserted near the center comes out clean). Let the cake cool completely in the pan.

While the cake cools, prepare the sauce: In a saucepan, whisk together the brown sugar and cornstarch until combined. Add the apple cider and stir in the heavy cream, butter and a pinch of salt.

Place the saucepan over medium‑high heat and whisk constantly until large bubbles form around the edge of the pan (about 3 minutes). Then reduce the heat to low and continue to whisk until the sauce thickens (about 2 minutes).

Once the cake is cool, pour (or drizzle) the warm caramel cider sauce over the top of the cake. Alternatively, you can slice the cake and serve each piece topped with vanilla ice cream and a generous drizzle of the sauce.