1. Preheat the oven to 350° F. Grease a 10-cup to 12-cup Bundt pan. Set aside. Using an electric mixer on high speed, beat together the butter and granulated sugar until light and fluffy. Add the eggs one at a time, beating well after each addition. Add lime juice, zest, vanilla, baking powder and salt. With mixer on low, gradually add the flour (beating just until combined). Turn off the mixer.
2. Chop one cup of pistachios. Fold into the batter. Pour batter into Bundt pan. Bake for 1 hour to 1 hour 20 minutes or until a skewer inserted into middle of cake comes out clean. Let cool in pan for 15 minutes. Invert onto a wire rack. Turn upright to let cake cool completely.
3. Bring a small saucepan of water to a boil. Add the remaining cup of pistachios. Blanch them for 3 minutes. Drain. Place in a bowl of ice water. Let cool, and drain again. Spread the pistachios onto a clean dish towel. Fold to cover. Gently rub the towel to loosen the skin of pistachios. Peel the skins off the pistachios, and discard the skins.
4. Place the peeled pistachios in a food processor. Puree until smooth. Add powdered sugar. Continue to puree until a smooth paste forms. Drizzle in the oil while pureeing. Spoon the mixture into a bowl, and refrigerate until very cold.
5. Add 1/2 cup of pistachio paste to a blender. Add heavy cream. Blend until thick and creamy to soft peaks. Refrigerate until ready to serve. When cake is completely cooled, spoon the pistachio cream over the top. Sprinkle with additional lime zest and chopped pistachios. Garnish with lime slices.
   
   Note: Extra pistachio paste can be refrigerated and used as a spread on toast or pastries. Extra pistachio cream can be piped into cream puffs or croissants.

Per Serving: Calories: 960, Fat: 59 g (30 g Saturated Fat), Cholesterol: 265 mg, Sodium: 300 mg, Carbohydrates: 97 g, Fiber: 4 g, Protein: 15 g