• Preheat your oven to 180 °C (350 °F). Grease and line a loaf pan with parchment paper.
• Boil 30ml of milk with the black tea bag. Set aside.
• In a clean bowl, beat the egg whites until soft peaks form. Gradually add 50g sugar and continue beating until stiff peaks form. Set aside.
• In a separate bowl, cream together the butter and 150g sugar until pale and fluffy. Add the vanilla, then beat in the yolks one at a time until smooth.
• Gently mix in the flour, stirring until just combined.
• Using a spatula, gently fold in the whipped egg whites. Be careful not to deflate the batter.
• Split the batter evenly into two bowls. In the first batter, mix in 30ml of milk.
• In the other, mix in the cinnamon, allspice, and milk that’s been steeped with black tea.
• Alternate spoonfuls of plain and spiced batter into your prepared pan. Use a skewer or chopstick to make gentle figure-8 swirls — don’t overmix!

Crumb Topping

• Combine the crumb topping ingredients, then using your fingers, break them into chunks and sprinkle evenly over the top.
• Bake for 40–50 minutes, or until a skewer inserted in the center comes out clean. Cool slightly before removing from the pan.

Drizzle

• Once the loaf is mostly cool, whisk together powdered sugar and milk, then drizzle generously over the top.