PLACE the butter, shallots, Thai basil, curry paste, lemon zest and salt in a large bowl and whisk until combined. Reserve the compound butter.
The herb salad:
PUT the tarragon, Thai basil, mint and parsley into a large bowl and drizzle with the lemon juice and oil.
USE your hands to mix the herbs together and season the salad to taste with salt and pepper. Reserve the salad.
To serve:
PREHEAT the broiler to high.
DIVIDE the escargots among 3 broiler-safe escargot dishes (each typically has 6 spaces).
SPREAD each escargot with plenty of the reserved butter, dividing it evenly among all the escargots and mounding it on top of each escargot.
PLACE the dishes on a sheet pan and transfer the sheet pan to the broiler.
BROIL the escargots, rotating the tray as needed so they cook evenly, until the butter begins to brown, about 5 minutes. (Depending on the strength of your broiler, the snails might use more or less time, so keep an eye on them.)
CAREFULLY place the baguettes in the bottom of the hot oven to warm while the escargots cook.
TRANSFER the escargots dishes to large plates and place a piece of baguette alongside each one.
CUT the reserved lemon into wedges and divide among the plates along with herb salad on the side. Serve immediately.