Preheat the oven to 375°. Spray a loaf pan with nonstick cooking spray. In a medium bowl, whisk the cake flour with the baking powder and salt.
In an electric stand mixer, beat the butter with the sugar at medium speed until pale and fluffy, about 2 minutes, scraping the sides. Add the eggs one at a time, beating well between additions. At low speed, beat in the flour mixture just until incorporated. Beat in the milk, and vanilla, scraping down the side of the bowl as necessary.
Scrape the batter into the prepared pan and bake for about 1 hour 15 minutes, until the cake is golden and a toothpick inserted in the center comes out clean. Transfer the pan to a rack and let the cake cool for 20 minutes. Unmold the cake and let cool completely, about 3 hours.
Light a grill. Using a serrated knife, cut the pound cake into small cubes. Cut the peaches into 1½ inch wedges and sprinkle with sugar. Don’t cut your peaches too thin or they will not hold up well on the grill. Build kabobs by alternating each. Lightly oil the grate and brush the pound cake and peaches with extra Grassland butter. Grill the slices over moderate heat, turning once, until toasted, about 2 minutes.
Remove from grill and serve immediately.
