Preheat the oven to 375°F. Grease muffin tins.
In a small saucepan, bring the milk to a gentle simmer over low heat, then immediately remove the pan from the heat—do not allow the milk to boil. Add the Earl Grey tea bags and steep for about 15 minutes, then discard the tea bags.
In a medium sized mixing bowl, combine the canola oil, honey, ¼ cup of the brown sugar, yogurt, lemon zest, vanilla, eggs and stir until well combined. Add the tea steeped milk and stir to combine.
In a large mixing bowl add all purpose flour, 1 cup of whole wheat flour, baking powder, and salt and stir until combined. Make a well to pour the wet ingredients. Gentle fold wet ingredients into dry ingredients.
Fole blueberries into the batter, taking care not to over mix. Divide the batter evenly among the muffins cups.
In a small bowl, combine the remaining ¼ cup brown sugar, ½ cup of whole wheat flour, the butter, cinnamon, and nuts. Mix together with your hands until a crumbly mixture forms. Sprinkle the streusel topping over the batter, dividing it evenly.
5. Bake for 20 minutes, or until a toothpick inserted into the centre comes out clean.