Put the 2 tablespoons of heavy cream and the 1 teaspoon of lavender into a small saucepan, bring to a simmer then turn off the heat and let steep for 7 minutes
Strain the lavender out of the cream and let cool
Whip the butter and cooled caramel together until it's creamy
Add the heavy cream, salt, and powdered sugar
Whip until light and fluffy
Put into a piping bag and pipe around the edge onto the cooled macaron shells
Add a dollop of caramel in the middle and top with another shell
Put them in an airtight container and refrigerate 24 hours to mature the macarons. Then let them get to room temperature and enjoy!