To make the custard: Combine the milk, 1/4 cup of the sugar, and the lavender in a medium saucepan and bring to a boil over medium-high heat. Remove from heat and let sit for at least 30 minutes.
Combine the eggs, egg yolks, and remaining 1/4 cup sugar in a medium bowl and beat until light and frothy. Gradually add half the boiled milk mixture, stirring constantly. Gradually add the yolk mixture back to the milk mixture in the pan, stirring constantly. Strain the custard into a clean container and let cool to room temperature. Cover and refrigerate overnight. (This may be done 1 day in advance.).
To make the caramel: lightly oil six 4-ounce ramekins or custard cups. Combine all the caramel ingredients in a small pan. Cook over medium heat, stirring occasionally, until the sugar turns a light amber color, about 10 to 12 minutes. Pour an 1/8-inch layer of caramel into the bottom of each prepared ramekin or custard cup.
To make flans: Preheat the oven to 325°F Place the ramekins or cups in a deep baking pan. Carefully pour the custard into the ramekins or cups.Add warm water halfway up the sides of the ramekins or cups. Bake for 25 to 30 minutes, or until the edges have set and a nickel-sized spot in the center jiggles slightly when a flan is shaken. Remove the baking pan from the oven and remove the flans from the baking pan.
Let cool completely. Place in the fridge at least 6 hours or over night.
Tip each flan out of the ramekin or cup onto a dessert plate and garnish with strawberries and mint.