1-Preheat the oven: Preheat the oven to 350°F (180°C).

2-Line the pan: Line a 9-inch (23 cm) loaf pan with parchment paper and lightly grease with olive oil.

3-Mix dry ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, and cinnamon.

4-Mix wet ingredients: In a large bowl, whisk the pumpkin puree, brown sugar, eggs, and ⅓ cup olive oil until smooth.

5-Combine mixtures: Add the dry ingredients to the wet ingredients and whisk until combined and no dry flour remains.

6-Divide batter: Divide the batter into three equal parts.

7-Layer in the pan: Pour one-third of the batter into the pan, then drop half of the chocolate-hazelnut spread (about ½ cup) in small spoonfuls randomly over the batter. Repeat with the second third of batter and the remaining chocolate-hazelnut spread (the other ½ cup), then finish with the last third of batter.

8-Swirl batter: Run a skewer through the batter and spread in a zigzag pattern three times to create swirls, being careful not to overmix.

9-Sprinkle nuts: Sprinkle the ground hazelnuts evenly over the top.

10-Bake cake: Bake for 1 hour and 15 minutes, rotating the pan halfway through. The cake is done when the nuts are golden and toasted, the center springs back when pressed gently, a skewer inserted into the center comes out clean, and the internal temperature reaches 212°F (100°C).

11-Cool cake: Let the cake cool in the pan for 10 minutes, then remove it using the parchment paper and transfer to a wire rack to cool completely.