For the lavender crème brûlée, put the milk and whipping cream in a saucepan and add the lavender flowers. Bring to a boil once, remove from heat again and steep covered for about 15 minutes to bind the aroma. Strain and blend with crème fraîche. (Or simply flavor this mixture with the lavender essence).
Meanwhile, scrape out the pith of the vanilla bean and mix with egg yolks, granulated sugar and vanilla sugar. Beat in a bowl over steam until fluffy. Now gently mix the lavender-milk mixture with the yolk mixture and pour into small ramekins.
Preheat the oven to 150 °C. Fill a baking dish about 2 cm high with hot water (the ramekins should be about halfway in the water) and place the ramekins in it. Allow to set in the hot oven for 30-40 minutes. Lift out, let cool briefly, and refrigerate for 4-6 hours.
Before serving, sprinkle a little brown sugar on top of each crème and caramelize to a crisp using a Bunsen burner (available in specialty stores) or under the broiler in the oven. Lift out the lavender crème brûlée and garnish with the lavender flowers as desired.