Bring 1 cup red wine, ¼ cup sugar, ½ tsp. ground allspice, ¼ tsp. ground cloves, and a pinch of kosher salt to a simmer in a medium saucepan over medium-high and cook, stirring and scraping down sides of pan, until thickened and syrupy, 10–12 minutes. Remove wine syrup from heat.
Melt 2 Tbsp. unsalted butter in a small nonstick skillet with a lid over medium heat. Add 1 pear, peeled, halved, cored, cut sides down, and cover pan. Cook pear until golden brown underneath and slightly tender, about 5 minutes. Remove from heat and sprinkle all over with a pinch of kosher salt and remaining 2 tsp. sugar; turn to coat.
Scoop some vanilla ice cream into bowls; top each with a pear half and generously drizzle wine syrup over. Sprinkle with flaky sea salt if desired.
