Line a baking sheet with parchment paper.
Chop 10 ounces white chocolate and place it in a heatproof bowl.
Warm 3 tablespoons heavy cream until hot but not boiling.
Pour the warm cream over the chopped white chocolate.
Wait 1 minute.
Stir slowly until the mixture looks smooth and glossy.
Add 1 tablespoon softened butter and stir until fully melted in.
Stir in 1/8 teaspoon fine salt and 1/2 teaspoon vanilla extract until combined.
Fold in 2 teaspoons finely grated lemon zest until evenly distributed.
Let the mixture cool for 2 minutes.
Stir in 2 tablespoons powdered sugar until smooth.
Stir in 1 tablespoon fresh lemon juice gently until combined.
Taste the mixture.
Add 1 drop natural lemon oil only if needed, then taste again before adding more.
Cover the bowl and chill for 45–60 minutes until the filling is scoopable.
Scoop 1 tablespoon portions of the chilled filling onto the parchment-lined baking sheet.
Roll each portion quickly into a ball.
Chill the rolled centers for 20 minutes.
Melt 8 ounces of coating chocolate in short bursts, stirring often until smooth.
Stir in up to 1/2 teaspoon neutral oil only if the coating thickens.
Dip the cold centers in the melted coating chocolate.
Tap off the excess coating.
Top immediately with crushed vanilla wafers or graham crumbs and any optional toppings if using.
Let the truffles set at cool room temperature or chill for 10 minutes until the coating is firm.
Let the truffles sit for 10 minutes before serving.