||Preheat oven to 350 degrees. Line an 8-inch cake pan with parchment paper, and brush sides and bottom with 1 teaspoon olive oil. :::::::::::
Wash the grapes and discard stems. Dry grapes well, and set aside. In a large bowl, whisk together the eggs, milk, ½ cup olive oil, vanilla, lemon zest and ½ cup sugar. Blend thoroughly. Stir in the flour, baking powder and salt, and mix well until smooth. :::::::::::
Pour the batter into the prepared pan. Place the grapes evenly, about ¼ inch apart, in concentric circles on top of the batter to cover the entire surface. Press the grapes halfway into the batter. Scatter the pignoli evenly on the cake and sprinkle with 1 tablespoon sugar. Bake for 45 minutes, at 350 degrees, until golden and firm to the touch. Remove from the oven, and cool on a rack for 5 minutes, then turn out to finish cooling.