Preheat the oven to 350°F (175°C).

In a food processor, pulse the pistachios until finely ground.

In a mixing bowl, combine flour, baking powder, and salt. Set aside.

In another bowl, beat the butter and granulated sugar until creamy.

Add the ground pistachios, lemon zest, and vegetable oil; mix well.

Add eggs and egg white one at a time, mixing after each addition.

Mix in the sour cream, vanilla extract, and almond extract (if using).

Gradually add the flour mixture until just combined.

Pour the batter into a greased 9x13 inch baking dish.

In a separate bowl, beat the cream cheese until smooth, then add the powdered sugar and additional vanilla extract.

Drop spoonfuls of the cream cheese mixture on top of the batter and swirl with a knife.

Pour buttermilk over the top, without stirring.

Bake for 45 minutes or until golden and set in the center.

Allow to cool before serving.