In a medium saucepan over medium heat, melt 3 tablespoons unsalted butter. Add the finely minced shallot and cook, stirring, until translucent and soft, about 3–4 minutes. Add the minced garlic and cook 30–45 seconds until fragrant, taking care not to brown.

Deglaze and reduce

Pour in 1 cup dry white wine and raise heat to medium-high. Scrape any browned bits from the pan and bring to a simmer. Reduce the wine by about two-thirds until roughly 1/3 cup remains, about 6–8 minutes — this concentrates the flavor and removes harsh alcohol.

Add stock and cream

Add 1 cup chicken or vegetable stock and bring back to a gentle simmer. Reduce the liquid by about one-third, 5–7 minutes, then reduce heat to low and stir in 3 tablespoons heavy cream.

Mount with butter and finish

Remove the pan from the heat. Whisk in the 2 tablespoons cold unsalted butter, one cube at a time, until the sauce is glossy and slightly thickened (this is mounting). Whisk in 1 teaspoon Dijon mustard and 1 teaspoon fresh lemon juice. Taste and season with 1 teaspoon salt and 1/2 teaspoon freshly ground black pepper, adjusting to taste. Stir in 1 tablespoon finely chopped parsley. Keep warm on the lowest heat or hold in a warm spot; do not boil once butter is mounted or sauce may separate.

Protein (seared chicken — optional)

Prepare the chicken

Pat the 2 chicken breasts dry with paper towels. If thick, butterfly or lightly pound to an even thickness about 1/2–3/4 inch for even cooking. Season both sides with 1/2 teaspoon salt and 1/4 teaspoon black pepper.

Sear

Heat a large skillet over medium-high heat and add 1 tablespoon olive oil. When oil shimmers, add chicken breasts and sear without moving until a golden crust forms, about 4–5 minutes. Flip and cook the second side 4–5 minutes more, until internal temperature reaches 165°F (74°C) or until juices run clear. Transfer to a plate and let rest 5 minutes before slicing.

Optional finishing

If you like, deglaze the chicken skillet with 1/4 cup wine or stock during resting and scrape up fond, then add that liquid to the prepared Carte Blanche sauce for extra depth.

To serve

Warm 2 cups steamed baby potatoes or buttered pasta. Slice the rested chicken breasts against the grain into 1/4-inch slices (if using fish, cook and portion similarly).

Place potatoes or pasta on plates, top with sliced chicken, and generously spoon the Carte Blanche sauce over the protein and starch. Garnish with additional chopped parsley or microgreens and serve with lemon wedges on the side to brighten flavors.

Serve immediately. Leftover sauce can be refrigerated up to 2 days; gently rewarm and whisk — add a splash of stock or cream if it tightens.