Add heavy cream and 2 Earl Grey tea bags (or 2 teaspoon Earl Grey loose leaves) in a jar with a lid and let it rest in the fridge overnight.
The next day, preheat the oven to 400°F. Line a baking sheet with parchment paper.
Remove Earl Grey tea bags from the heavy cream, pressing them with a spoon to extract more flavor.
In a large bowl, mix together dry ingredients: flour, sugar, baking powder and Earl Grey tea. If using tea bags, cut the 2 tea bags open, add the tea and discard the bags. If using loose tea, grind the leaves until fine. Whisk to mix.
Add cold butter, grated or cubed into small pieces. Using your fingers, a pastry cutter or a fork, press the butter and the dry ingredients together until you get the consistency of pear-sized crumbs. Do not overwork the dough: that will give you tough scones.
In a small bowl, add the egg and Earl Grey or vanilla extract and quickly whisk them together.
Add egg mixture to large bowl, and using your hands, combine the ingredients.
Add heavy cream and, with your hands, mix until ingredients are combined and dough starts to form.
Turn the dough into a floured surface and form a disk, about 1 to 1 ½ inch thick. Use a bench scraper or sharp knife to divide disk into 8 triangles.
Place shaped scones in the baking sheet, and bake them for 15 to 18 minutes, until lightly golden on top. Do not bake for more than 18 minutes.
Remove them from the oven and allow the scones to cool for 30 minutes.
To make the glaze, stiff the icing sugar to avoid clumps.
In a small bowl, combine icing sugar, Earl Grey extract (if using) and lemon juice until glaze forms.
Use a spoon or whisk to drizzle the citrus glaze over the scones. Don’t make the glaze ahead: it sets really fast, so make it when ready to pour over the scones.