Separate eggs; let stand at room temperature 30 minutes. Lightly brush the inside of six 6-oz. ramekins or custard cups with 1 tablespoon melted butter. Dust each with 1/2 teaspoon sugar.
Preheat oven to 350°. In a small saucepan, combine milk and herbs; bring just to a boil. Immediately remove from heat; let stand 10 minutes. Strain milk through a fine-mesh strainer; discard herbs.
Place flour and 2 tablespoons sugar in a large bowl; whisk in yolks, lemon zest, lemon juice, remaining melted butter and strained milk. In a separate bowl, beat egg whites on medium speed until foamy. Gradually add remaining 4 tablespoons sugar, 1 tablespoon at a time, beating on high after each addition until sugar is dissolved. Continue beating until stiff glossy peaks form; fold gently into flour mixture. Divide among ramekins.
Bake until tops spring back when lightly touched, 17-20 minutes. (Cakes will fall slightly.) Sprinkle with coarse sugar; cool 5 minutes on a wire rack. Serve warm.