Match your recipe type: for sauces/cocktail-style pours, favor Pastis or Anisette; for savory braises, favor dry vermouth with a small anise boost.
Use the listed ratio as a starting point, then adjust once the sauce simmers or the batter rests (flavor intensifies quickly with liqueurs).
If your substitute is sweeter than Pernod (notably Anisette), reduce the swap amount by about 25% or balance with a squeeze of lemon/extra salt.
If the substitute is stronger (like absinthe), start lower (75%) and add only after tasting the warmed sauce.
For non-alcohol swaps (star anise syrup), simmer for 1–2 minutes after adding so the aroma blooms and the flavor integrates.