1. Preheat your oven to 350°F (175°C) and position a rack in the center. Grease a 9-inch springform pan with butter and line the bottom with a round of parchment paper.

2. In a medium bowl, whisk together the all-purpose flour, baking powder, kosher salt, and ground pistachios. Set aside.

3. In a large bowl or the bowl of a stand mixer, beat the softened butter, granulated sugar, and drained ricotta on medium-high speed for a full 4-5 minutes, until the mixture is very light, pale, and fluffy.

4. Add the room temperature eggs one at a time, mixing well after each addition. Mix in the vanilla extract and lemon zest.

5. Add the dry ingredient mixture to the wet ingredients. Mix on low speed or by hand with a spatula just until no dry streaks remain. Do not overmix.

6. Pour the batter into the prepared pan and smooth the top into an even layer. Bake for 45-55 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean.

7. Let the cake cool in the pan on a wire rack for 10-15 minutes. Then, carefully run a knife around the edge and release the springform collar. Allow the cake to cool completely before topping and serving.

8. Once cool, dust with powdered sugar and sprinkle with chopped pistachios, if desired. Slice and enjoy!