01 - Preheat oven to 350°F. Grease and line three 8-inch round cake pans with parchment paper.
02 - Heat the milk until steaming without boiling. Add Earl Grey tea bags and steep for 15 minutes. Remove tea bags and allow milk to cool completely to room temperature.
03 - In a medium bowl, whisk together all-purpose flour, baking powder, and salt until thoroughly blended.
04 - In a large bowl, beat softened unsalted butter and granulated sugar until pale and fluffy, approximately 3 minutes. Add eggs one at a time, mixing well after each addition. Stir in vanilla extract and lemon zest.
05 - With mixer on low speed, add dry ingredients in three additions, alternating with cooled Earl Grey milk. Begin and end with flour mixture. Mix until just combined, being careful not to overmix.
06 - Divide batter evenly among prepared pans. Smooth tops and bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out clean.
07 - Let cakes cool in pans for 10 minutes, then turn out onto cooling racks to cool completely before frosting.
08 - In a small saucepan, bring water and granulated sugar to a simmer. Add Earl Grey tea bags and steep for 10 minutes. Discard tea bags and allow syrup to cool completely.
09 - Beat softened unsalted butter until creamy. Gradually add powdered sugar, alternating with whole milk, beating until smooth and fluffy. Mix in vanilla bean paste and salt until well incorporated.
10 - Level cooled cakes if necessary. Brush each cake layer generously with London Fog syrup. Spread frosting between layers and over top and sides of cake in a smooth, even layer.
11 - Garnish with dried edible flowers and lemon zest if desired. Refrigerate for 30 minutes before slicing to ensure clean cuts.