In a small saucepan, combine shallot, bay leaf, and white wine. Simmer over medium heat until almost fully reduced. Taste it as you go. If you feel astringency at the back of your throat, the alcohol hasn't cooked off yet. Raw wine throws a sharp scent that pushes your face back. Step away a few seconds, then come in from the side. You'll know it's ready when that scent is gone and you smell fruit and shallot instead.

Add crème fraîche and reduce by half, about 3–4 minutes. The crème fraîche is what makes this hold. A classic beurre blanc has none, which is why it splits the moment you take your eye off it.

Whisk in butter one tablespoon at a time until half the butter is incorporated. Remove from heat.

Off the heat, add remaining cold butter all at once and whisk vigorously to emulsify.

Season with lemon juice, lemon zest, and salt. Keep warm, stirring occasionally. Take on and off low heat to maintain emulsion if needed.

Pat salmon filets dry with a paper towel and season with kosher salt.

Heat a medium skillet over medium-high heat with a drizzle of olive oil.

Once hot, place salmon skin-side down. You should hear a sizzle; if not, remove it and let the oil heat more. Press gently with your hand or a kitchen weight to ensure even skin contact.

Sear for 4–5 minutes, until skin is deeply golden and crispy. You'll know it's ready to flip once it releases from the pan. It sticks because the crust is still forming, so don't nudge it around if it's not releasing. The protein will almost always tell you when it's ready. Flip and cook for another 1–2 minutes until just done.

Just before serving, gently whisk chive oil into the beurre blanc to "break" the sauce.

Plate the salmon skin-side up and spoon broken beurre blanc over the top or around the side.