Preheat your oven to 350°F (175°C). Grease a 9-inch round cake pan and line the bottom with parchment paper.

In a large bowl, whisk together the flour, baking powder, and salt.

In a separate bowl, beat the white sugar, brown sugar, eggs, melted butter, vegetable oil, and vanilla extract until fluffy.

Gradually fold the dry mixture into the wet batter. Stir in the milk, Greek yogurt, and spinach puree until smooth. Add green food coloring and cayenne pepper if desired.

Pour the batter into the prepared pan and tap gently to release air bubbles. Bake for 25-28 minutes, or until a toothpick comes out clean.

Allow the cake to cool in the pan for 10 minutes, then invert onto a wire rack to cool completely.

For the frosting, beat together powdered sugar, softened cream cheese, and vanilla until light and fluffy. Spread over cooled cake and top with crushed pistachios and mint leaves.