Apple Fritters with Orange Glaze

Name: Apple Fritters with Orange Glaze
Ingredients: 2 cups all-purpose flour; 1/2 cup sugar; 2 1/4 teaspoons baking powder; 1 teaspoon fine salt; 2 large eggs; 3/4 cup whole milk; 3 tablespoons unsalted butter, melted and cooled slightly; 2 teaspoons grated orange zest from 1 navel orange (set aside orange to use for juice in glaze); 1 teaspoon pure vanilla extract; 2 Golden Delicious apples (1 pound total), peeled, cored, cut into 1/4-inch-thick slices; About 3 cups vegetable oil; 1 cup confectioners' sugar plus more for dusting; 3 tablespoons orange juice from navel orange; 1/2 teaspoon pure vanilla extract; Deep-fat/candy thermometer