Preheat the oven to 180°C and lightly spray a doughnut pan with cooking oil.
In a small microwave safe bowl, heat the milk until warm and add the earl grey tea bag. Sit aside and let steep.
In a small bowl, make the crumb topping by mixing together the flour, brown sugar, cinnamon and dairy-free butter with a fork until a crumb-like texture forms. Set aside in the refrigerator to keep cold.
In a medium size bowl add flour, baking powder, and salt and mix gently with a whisk to combine.
In a large bowl, whisk together the egg, sugar, vanilla and oil. Add in dry ingredients and mix through, slowly adding in the dairy-free milk that's been infused with the earl grey tea, until the batter is smooth.
Pour batter into a large piping bag or ziplock bag and cut off the tip. Pipe the batter into the doughnut pan ensuring each hole is only half full. Sprinkle the crumb mixture over the top in an even layer.
Place in the oven and bake for 9 minutes or until cooked through. Let the doughnuts cool in the pan for 5-10 minutes (until the top get’s crunchy) before turning out onto a wire rack to cool completely.
To make the glaze, whisk together all the ingredients until smooth. Drizzle the glaze over the doughnuts. These doughnuts are best eaten the day of baking as after that the crunch topping can go soft.