Preheat oven to 300°F. Place 4 ramekins in a baking pan.

In a small saucepan over medium heat, bring vanilla pod, cream, and lavender to a boil. Strain to remove lavender buds and bean.

In a medium bowl, whisk together egg yolks and sugar. While whisking, starting very slowly at first, pour hot cream into egg-sugar mixture. Strain egg and cream mixture.

Pour into ramekins, then pour boiling water into baking pan until water comes halfway up the sides of the ramekins.

Bake for 30 minutes; the center will still be jiggly. Remove from water, cover, and cool completely.

Increase oven temperature to 350°F

Use your finger to rub butter into a small circle on parchment paper. Dust with a layer of sugar. Bake for 5 minutes, or until sugar starts turning brown. Remove sugar circles and let cool completely.

To serve, place a crisp sugar circle on top of each crème brûlée.