Lavender Ermine buttercream Macaron

Mise-en-place: 
0 Pre-heat oven to 300F
1 Wipe with vinegar the silicon mats, bowls and baking trays. Print templates if using.
2 Weight all the ingredients in separate bowls
3 The egg whites can be directly taken from the fridge and do not require aging.
Prepare dry ingredients: 
4 Add egg white powder to the bowl containing the granulated sugar and mix well.
5 If the almond flour is not super fine, I recommend doing 2-3 pulses in a food processor. Only do this for short amounts of time.
6 Sift the almond flour and powdered sugar. Do this two times.
7 Note: keep all the containers covered with lids.
Prepare the French Meringue:
8 In the bowl of a stand mixer fitted with a whisk, whip egg whites on medium speed until foamy/frothy.
9 Gradually add the granulated sugar/ powdered egg white mixture, continue whipping on medium speed until glossy stiff peaks
Macaronage:
10 Add half of the meringue to the almond flour / powdered sugar mixture.
11 Add gel food coloring
12 Fold gently with a spatula until the dry ingredients are incorporated
13 Add the remaining meringue
14 Fold gently until the batter becomes glossy and falls off the spatula like ribbons.
Piping: 
15 Fit a round tip (e.g., Wilton 12) in a pastry bag, place the bag inside a tall measuring cup or a deli container, wrap the bag in the edges of the cup to keep it open
16 Pour the macaron batter into the pastry, remove from the cup
17 Pipe circles onto the tray with silicon mat or pre-printed template under a piece of parchment
Resting and baking:
18 Let the piped macarons rest on the kitchen counter until a skin is developed, you will be able to gently touch them without batter sticking to the fingers.
19 Once the skin is formed, place inside the oven, bake at 275-300F (this will depend on your location and other factors like humidity) for 15-18min.
20 Use an oven thermometer to make sure the oven is not too hot.
21 Let the macarons cool before removing from the baking surface
Filling macarons
22 Fit a small tip, I recommend tips like 4B, 1M for nice piping designs, inside a pastry bag. Place inside a tall measuring cup or deli container.
23 Pour the ganache inside the bag
24 Take 1 macaron shell, pipe the ganache in the center
25 Take another macaron shell and sandwich the filling. The best ratio of macaron to filling is 2:1
Ermine Buttercream Recipe:
34 In a small saucepan, heat milk to a gentle boil with the lavender flowers. Turn off the heat and let steep for 10 minutes. 
35 Strain the lavender flowers. 
36 Pour the milk back into the saucepan, add sugar, salt and cornstarch, whisk until smooth.
37 Bring to a boil, it should thicken, strain into the bowl of a mixer and chill.
38 Beat mixture with paddle attachment until smooth. 
39 Gradually incorporate butter until smooth and emulsified.