Fresh leafy herbs are kind of like buttermilk. You always buy them with good intentions of using all of it before it goes bad, but sometimes it's just not possible. Because they're so perishable, everyday that it sits in the fridge means there's more and more of it that can't be salvaged.
I bought what seemed to be the biggest bunch of tarragon last week. I was able to use most of it, but was trying to come up with ideas to use up the leftovers. A simple syrup? Hollandaise? But the only practical solution was to use it to flavor butter. A compound butter if you're in a professional kitchen.
Herb butters are a great way to use up those last bits of herbs. Everything gets mixed with some softened butter, rolled like the tasty and aromatic cigar that it is, and gets thrown in the freezer. Just slice as much as you need (carefully) straight from the freezer.
Throw a knob of it into your green beans/ asparagus/ peas/ favas at the end when you're sauteeing it. Melted, and it becomes a decadent dipping medium for prawns or lobster. Slip a few coins of it under the skin of your chicken before you roast it. Or one of the classic ways of using compound butters is a thick slice over your steak just before it goes to the table, melting it into fatty deliciousness.
Lemon Tarragon Butter
Makes 1/2 a cup
Any fresh herb you have hanging around will do. Adjust the amount accordingly if using a strong herb like rosemary or sage.
1/2 cup unsalted, cultured butter, softened* (or regular butter)
1/4 cup loosely packed tarragon leaves
zest of half a lemon
2 tsp lemon juice
1/4 tsp salt
In a small bowl, combine the butter, coarsely chopped tarragon, zest, juice, and salt. Mix well.
Take a small rectangle of parchment and spoon the butter along the long side of the paper. Carefully roll into a tight log and twist off both ends. Like you were making a really big butter candy.
Put into the freezer until needed. Using a sharp knife, carefully slice off what you need, right through the parchment and rewrap tightly in cling film.
*Cultured butter is when cream has been fermented slightly before it gets churned into butter. This process gives the butter a more complex and aromatic flavor.