Greek Easter Bread (Tsoureki)

Ingredients

• 3/4 cup plus 1 tablespoon whole milk
• 1 (1/4-ounce) packet active dry yeast (2 1/2 teaspoons)
• 4 cups all-purpose flour, plus more for dusting
• 2/3 cup granulated sugar
• 1 teaspoon fine salt
• 1 teaspoon ground mahlepi (optional)
• 1/4 teaspoon pounded mastic crystals (optional)
• 8 tablespoons unsalted butter (1 stick)
• 2 large eggs
• 1 1/2 teaspoons finely grated orange zest (from about 1 orange)
• 1 red-dyed hard-boiled egg (optional)
• 1 large egg yolk
• 1/3 cup sliced almonds, toasted