Let me encourage people to grow French tarragon (make sure you don't buy a Russian tarragon seeding which is completely different in flavor). This plant is a perennial down to zone 5 and can be wintered in a garage for lower zones. It is easy to grown in pots as well as in the garden. I love having one right next to my back door and often grab a bite as I pass by. Yum.
Asparagus, Leek, and Fennel Soup
Adapted from: Serious Eats
Serves: 4 if it is the main dish or 6 if it is a side
2 T oil
1 large leek, white and pale green portions, finely chopped
1 fennel bulb, trimmed and thinly sliced (save some of the fronds for garnishing)
2 T all-purpose flour
4 c chicken or vegetable stock
2 pds asparagus, trimmed and cut in 1 1/2-in pieces
1 small handful minced fresh French tarragon leaves (plus a little more for garnishing)
2 T fresh lemon juice
creme fraiche thinned with some cream or milk, optional
Heat the oil in a 4- qt saute pan over medium-low heat until shimmering. Scoop the leek and fennel into the pot and stir in a big pinch of salt. Cook, stirring often until the vegetables are softened but not browned. Add the flour and stir while cooking until it is incorporated, about half a minute. Pour in the stock and bring to a simmer.
Add the tarragon and asparagus, reserving a about 8 spears. Return to a simmer and cook 6-8 minutes until the asparagus is tender. Add the lemon juice. Place the spears in a small bowl with a tablespoon or two of water and microwave for 1 minute. Remove from the bowl, drain, and cut each spear in half.
Blend the soup with an immersion blender or in batches in a countertop blender. You can blend it very smooth or a bit chunky if you like. Taste the soup and season with pepper and more salt if needed. Serve, garnishing with creme fraiche (if you are using), tarragon leaves, and fennel fronds. You may also drizzle a bit of olive oil over all.