Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius). Grease and flour four eight-inch (20-centimeter) round baking pans; I use the disposable ones.

Place the sugar, eggs, oil, lemon juice, and vanilla into a large mixing bowl and mix well. Add the flour, baking powder, and salt and mix well. Squeeze the tea bag into the cup, discard the tea bag, and add the brewed tea to the batter. Mix gently. Divide the batter among four mixing bowls; there should be about two and a half cups of batter for each bowl.

Color each bowl of batter a different shade of the same color. I set aside one bowl of batter to remain white and color only three bowls of batter. Add one drop of food coloring to one bowl, two drops to the second. And then three drops to the third. Mix each bowl. Add more color to the darkest batter to make it as dark as possible. Adjust the lighter colors by adding more coloring –only if necessary – to make sure there is enough contrast between them. Keep in mind that you can always add more color, but it is impossible to remove the color once you’ve added it.

Pour each bowl of batter into a prepared pan and bake for 30 to 35 minutes, or until a toothpick inserted in the cakes comes out clean. Let the cakes cool in the pans for 10 minutes and then turn them onto a wire rack to cool completely. Every once in a while, move the cakes around so they do not stick to the rack.

Pour a few inches of water into the bottom of a double boiler or a medium saucepan and bring to a boil, then reduce the heat to medium. Off the stove, put the sugar and warm water in the top of the double boiler or in a metal bowl that can sit on top of a saucepan without falling in. Whisk to dissolve the sugar. Add the egg whites, corn syrup, and salt, and beat for one minute with an electric mixer on medium-high speed.

Place the top of the double boiler (or metal bowl) over the gently boiling water and beat with an electric mixer on high speed for a full seven minutes. If the water starts to bubble too much, turn the heat down. Remove the pan from the heat, add vanilla, and beat for another 30 seconds, until the frosting is thick and has soft peaks.

If the cakes have a domes on top, trim the tops so they are flat. Eat the scraps. Stack the cakes and then trim the sides so they are straight.

Separate the cake layers on pieces of waxed paper. Place the lightest-colored cake layer on a serving plate and tuck pieces of waxed paper underneath it to catch any drips of icing. Spread the layer with one-fourth cup of white icing. Place the next darker-colored cake layer on top of the first layer and spread it with icing. Add the next darkest layer, spread it with icing; and then add the last, and darkest, layer to the stack of cakes, with the bottom side facing up.

Divide the remaining icing among four bowls. Leave one bowl white. Color the icing in each of the other bowls three graduated colors (I try to match the cake colors).

Ice the outside of each cake layer with the opposite icing color, so that the white cake is surrounded by the darkest color icing, and so on. Use a metal flat-blade spatula to scoop up the darkest color icing, and ice a band of that color around the bottom white cake layer. Scoop up the next lightest icing and ice another band the height of the next cake layer. It is OK if the colors blend a little; this helps achieve the graduated color effect. Repeat until you get to the top. Spread the white icing over the top of the cake and onto the first inch or so (from the top down) on the sides of the cake. Heat the metal spatula with some boiling water, dry it, and then use it to smooth the sides and top of the cake, blending the colors to achieve the “ombre” effect.