✓ Preheat oven to 350°F (175°C) and place a rack in the middle of the oven.

✓ Grease a 9‑inch round cake pan with a thin layer of butter; set aside.

✓ In a small saucepan, melt the 1/2 cup butter over medium heat, then stir in the 1 cup brown sugar until dissolved and bubbling – watch for a deep amber color.

✓ Remove the pan from heat and immediately stir in the halved pecans; the mixture will sizzle and coat the nuts.

✓ Pour the caramel‑pecan mixture into the prepared cake pan, spreading evenly with a spatula.

✓ In a large bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, ginger, and salt.

✓ In a separate bowl, combine granulated sugar, light brown sugar, vegetable oil, and eggs; beat until the mixture is pale and slightly thickened.

✓ Add pumpkin puree to the wet mixture and stir until smooth.

✓ Stir in buttermilk gradually, mixing just until incorporated.

✓ Fold the dry ingredients into the wet mixture in two additions, mixing on low speed until just combined.

✓ Carefully pour the batter over the caramelized pecan layer, allowing it to flow naturally and cover the nuts.

✓ Place the pan in the preheated oven and bake for 35–40 minutes, or until a toothpick inserted near the center emerges clean and the top is a deep golden brown.

✓ If the top begins to darken too quickly, loosely tent foil over the cake for the remaining baking time.

✓ Remove the cake from the oven and let it rest in the pan for 10 minutes.

✓ Run a thin metal spatula around the pan’s perimeter to loosen the edges.

✓ Place a large serving plate upside‑down over the pan and flip the cake onto the plate.

✓ Allow the cake to cool for an additional 15 minutes before slicing.

✓ Serve warm or at room temperature, optionally dusted with a light sprinkle of cinnamon or a dollop of whipped cream.