Parsnip Confit with Pickled Currants

Name: Parsnip Confit with Pickled Currants
Ingredients: 2½ lb. parsnips, peeled, halved lengthwise, quartered if large, woody core removed if large; 2 heads of garlic, halved crosswise; 1 4 piece ginger, scrubbed, sliced lengthwise into ⅛-thick planks; 3 large sprigs rosemary, divided, plus 1 Tbsp. rosemary leaves for serving; 1 Tbsp. plus 1 tsp. kosher salt; 3 cups extra-virgin olive oil; ½ cup dried currants; ¼ cup sugar; ½ cup plus 1 Tbsp. apple cider vinegar; 2 tsp. Aleppo-style pepper