Preheat oven to 340F. Butter and flour three 6-inch cake pans. Soak baking strips in water. (If you're making three 8" layers then double the batter, three 9" layers would need triple the batter.)
Sift dry ingredients (including sugar). Whisk to combine.
In a small saucepan over medium heat, combine milk, culinary lavender and loose black tea. Give it a quick stir. Let it simmer for about 10 minutes. Strain into a bowl to cool. Measure ½ cup for the batter. Reserve the rest for the buttercream.
In a medium bowl, combine the wet ingredients, including butter and ½ cup of the infused milk.
Combine the wet and dry mixtures. Whisk until combined.
Add damp baking strips to the cake pans.
Evenly distribute batter into each pans. I like to use a kitchen scale for precision.
Bake for about 30- 35 minutes or until the centers are set and springy to the touch.
For the Italian Meringue Buttercream:
Beat the egg whites, salt and cream of tartar, slowly add in 1/3 cup of sugar and continue beating until soft peaks form.
In a medium saucepan add the remaining sugar and 1/3 cup water then place on medium-low heat.
Stir until sugar melts and becomes clear.
Maintain at medium-high heat until temperature reads 235-240F.
Drizzle the sugar into the mixer immediately.
Run the mixer until meringue is cool/tepid, about 15 minutes. You can pack the bowl with ice or frozen peas if you want to speed the cooling down.
Switch to a paddle attachment. Add room temperature butter into running mixer one tablespoon piece at a time.
Add the salt and vanilla.
Beat until butter is combined and mixture has reached a silky consistency.
Distribute into multiple bowls.
Use food coloring to create a gradient of colors.
Transfer to piping bags. Snip off the tips of each bag.
For the Buttercream:
In a stand mixer, cream the room temperature butter until fluffy.
Sift in half of the confectioners sugar. Mix, then add the rest.
Add in a few tbsps of the infused milk mixture until you reach a desired consistency.
Add in 2 drops of lavender essential oil. Mix until combined.
Reserve about 1 cup. Add in purple food coloring. Transfer to a piping bag.
Add about the same amount of white to a piping bag. Add both the white and purple to one piping bag.
Reserve about 1 cup for the roses. Dye with pink and orange food coloring. Transfer to a piping bag fitted with a 127 tip.
Dye a small amount of buttercream green for a ring, which will be the base of your flower wreath.
Reserve a small amount for the white daisies.
Transfer the remaining white buttercream to 1 large piping bag.
For the Flowers:
Cut a square of parchment paper. Use a tiny bit of buttercream to glue down the paper onto a piping nail.
For the roses, pipe a small cone of very thick buttercream in the middle of the square.
Use a 127 tip with the pointy side up to make the petals.
Start with a spiral for the center.
Pipe small arches for each petal, pointing the tip outward as you get towards the outer petals.
For the daisies, add some white buttercream to a piping bag fitted with small petal tip. Pipe yellow in the center.
For the Assembly:
Pipe the purple lavender swirl between each layer.
Crumb coat the cake with the plain white buttercream. Smooth with a scraper and offset spatula.
Starting with the darkest pink, pipe the Italian Meringue gradient.
Smooth cake with a scraper.
Chill the cake for about 10-15 minutes.
Pipe a ring of green.
Attach flowers to the ring and pipe leaves to fill in the gaps.
Video
Notes
If you're in a hurry/are not a fan of buttercream then you could make this recipe as a bundt cake or mini bunts and top it with a glaze made from confectioners' sugar and a few tablespoons of the lavender milk tea. Piping buttercream flowers can be intimidating but I have some tips for you. First off sift your powdered sugar, lumps are the enemy! Mix a stiff batch of buttercream for the flowers' center cones upon which you will add the petals. Fill one side of your piping bag with a lighter shade of whichever color you're using and make sure the sharp end of your petal tip is aligned with that side. One more thing. When you're mixing colors add the dye in little by little. I use a toothpick to swipe in some color then mix and add more if needed. If your colors look a but too bright add a TINY bit of black in to tone things down.