Stir together all ingredients and transfer to a small bowl. Chill, covered, until ready to serve.
Beer battered asparagus:
1) Heat oil in a heavy saucepan until it reaches 190C.
2) Whisk together flour, salt, pepper and lemon zest in a bowl until combined. Add beer and whisk ingredients until smooth. Dip asparagus in batter to coat. Remove excess batter before frying. Gently transfer battered asparagus to oil and fry until golden. Stir gently to prevent asparagus from sticking together.
3) Transfer to a paper towel-lined baking sheet and keep warm in a preheated 100C oven.
*Cook's note: Other herbs may be substituted