Hot Cross Buns

INGREDIENTS

• 1/2 cup whole milk
• 3 cups all-purpose flour (13 ounces)
• 3/4 teaspoon fine salt
• 1 teaspoon pure vanilla extract
• 1/2 cup sugar
• 1 1/2 teaspoons pure vanilla extract
• 4 1/2 teaspoons active dry yeast (2 (1/4 ounce) packages)
• 2 cups confectioners' sugar, sifted
• 1/4 teaspoon finely gated lemon zest
• 1 egg beaten, for brushing
• 1/3 cup unsalted butter, melted, plus as needed
• 1/2 teaspoon grated nutmeg
• 1/2 teaspoon ground cinnamon
• 1/4 teaspoon ground ginger
• 1 large egg yolk
• 2 tablespoons milk
• 1/2 cup currants, plumped in the microwave and cooled
• 1/2 cup water