Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking pan generously with unsalted butter.

In a mixing bowl, cream together the softened unsalted butter and cream cheese on medium speed until smooth and fluffy, about 2-3 minutes.

Incorporate the whole egg and egg yolk into the creamed mixture and beat until smooth, about 1 minute.

Gradually sift in the icing sugar while mixing on low speed, then blend on medium until creamy and free of lumps, about 2 minutes.

In a separate bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt until evenly combined.

Slowly add the dry mixture to the wet ingredients, mixing on low speed just until combined, about 30 seconds.

Gently fold in the chopped pecans using a rubber spatula.

Pour the batter into the prepared baking pan and smooth the top. Bake for approximately 60 minutes.

Allow the cake to cool in the pan for about 20 minutes, then cut into squares and serve warm or at room temperature with whipped cream or ice cream.