If you have your own garden (or friends who do), you'll likely have access to fresh squash blossoms - or if you shop at a market that carries a selection of specialty produce, it's worth asking the buyer if they can order some for you. This is a terrific first course dish devised by Cal Stamenov, Executive chef of Bernardus Lodge in Carmel Valley. His technique is unusual but user-friendly. Although there's a bit of work in assembling the blossoms, they can be cooked a day in advance of serving. If chervil isn't available or to your liking, substitute fresh basil for the sauce.
Make the filling: place the goat cheese, cream cheese, and sour cream or yogurt (if using) in the bowl of an electric mixer. Blend on low. Beat in the olive oil in a slow, steady stream. Beat in the eggs one at a time. Add the chervil, chives, lemon juice, anise, pepper, and Tabasco, and mix just until blended. Set aside.
Stuff the blossoms: Remove the pistil from each squash blossom. Loosely wrap each in plastic wrap and fill with the goat cheese mixture. This can be done easily with a plastic piping bag, or use a small spoon. With rubber bands, tie off each end of the plastic wrap, forming a tight sausage.
Place the blossoms in barely simmering water (170 degrees F) for 20 minutes. Do not allow the blossoms to boil. Remove from the pan and place blossoms on a platter; refrigerate until cold and firm. Do not remove the plastic wrap until assembly.
Make the chervil sauce: Place the chervil leaves in a blender with the olive oil. Blend at high speed for 1 minute, then gradually add the water. Strain, discarding any solids.
Make the garnish: Top and tail the beans. Blanch in boiling water for 2 minutes, then drain and plunge into an ice bath to stop the cooking process. When cool, drain thoroughly.
Assemble the dish: Pour 1/4 cup of the chervil sauce in the center of a large chilled plate. Place the beans in a pile in the center of the sauce. Remove the plastic wrap and arrange the squash blossoms on top of and around the beans. Season with sea salt and lime juice, then garnish with chervil sprigs. Serve extra chervil sauce on the side.