Preheat oven to 200°C (400°F). Line a baking sheet with parchment paper. Lightly flour your work surface and roll each thawed puff pastry sheet once to smooth seams (about 1/8 inch). Using a 3-inch round cutter, cut 12 full rounds from the pastry (you will need 12 bases and 12 tops — cut an additional 12 smaller rounds about 1/2 inch smaller for the tops or use a smaller cutter to cut centers out of 12 of the rounds to create rims).

Build vol-au-vent shells

Place the 12 base rounds on the prepared sheet. Brush the edges lightly with egg wash (beat 1 egg with 1 tsp water). Place the 12 rim pieces (the larger rings or the rounds with centers removed) on top of the bases, pressing gently to adhere. Dock the centers of the bases lightly with a fork to prevent excessive puffing. Brush the rims with egg wash; save some egg wash for the tops (if using solid tops instead of rims).

Bake

Bake in the preheated oven for 12–15 minutes or until puffed and golden. If centers bulge up, prick briefly and gently push down. Remove from oven and transfer to a wire rack to cool. Once slightly cooled, using a small knife remove the soft inner portion of each base where necessary to create a hollow shell, leaving the rim intact to hold filling. Keep shells warm or store at room temperature for up to 2 hours.

Escargot and garlic-herb butter

Prepare garlic-herb butter

In a small bowl, mash the 6 tbs room-temperature butter with minced garlic, minced shallot, chopped parsley, chopped chives, Dijon mustard, lemon zest, salt, and pepper until well combined. Stir in 30 ml dry white wine to loosen the butter slightly and marry flavors. Taste and adjust seasoning. The compound butter should be soft but not runny.

Cook escargots

Heat a small skillet over medium heat. Add a small knob (about 1 tbs) of the compound butter to coat the pan. Add the drained escargots in a single layer and sauté for 1–2 minutes until warmed through. Deglaze the pan with 15 ml dry white wine, scraping any brown bits and allowing the alcohol to evaporate for 30–45 seconds. Remove pan from heat and toss escargots briefly with another 1–2 tbs of the compound butter so each snail is coated in garlic-herb butter.

Assembly & finishing

Fill shells

Preheat oven to 175°C (350°F) if shells have cooled and you plan to reheat briefly. Spoon about 1/2 to 3/4 tbs of the garlic-herb butter into the bottom of each vol-au-vent shell. Place one escargot in each shell (for larger shells, place two). Top each snail with an additional small dollop (about 1/2 tbs) of the compound butter so they will melt and glaze when warmed.

Warm to marry flavors

Place filled vol-au-vents on the baking sheet and warm in the oven for 6–8 minutes, until butter is melted and sizzling and shells are hot. Alternatively, broil for 1–2 minutes to brown the butter lightly — watch closely to avoid burning.

Finish and serve

Remove from oven. Brush exposed pastry lightly with 1 tbs melted butter for shine. Garnish each vol-au-vent with a sprinkle of chopped parsley and a small grind of black pepper. Serve immediately with lemon wedges on the side for squeezing.