White Sauce

In a small saucepan, gently warm the milk over low heat with the bay leaf, mustard seed, onion salt, and white pepper, allowing the aromatics to infuse for about 10 minutes without boiling. Remove from heat and strain out the aromatics.

In a separate medium saucepan, melt the butter over medium-low heat until fully liquefied and beginning to foam slightly. Be careful not to let it brown.

Add the flour to the melted butter all at once and stir vigorously with a wooden spoon or whisk to form a smooth roux. Cook the roux for 1 to 2 minutes, stirring constantly, to eliminate the raw flour taste.

Remove the roux from the heat briefly, then slowly pour in the warm infused milk a little at a time, whisking continuously after each addition to prevent lumps from forming.

Return the saucepan to medium heat and gradually whisk in the fish stock to adjust the consistency and add depth of flavor. Continue stirring until fully incorporated.

Cook the sauce over medium-low heat, stirring constantly, until it thickens enough to coat the back of a spoon smoothly. This should take approximately 8 to 10 minutes.

Taste the sauce and adjust seasoning with additional onion salt or white pepper as needed. Remove from heat and use immediately or press a sheet of plastic wrap directly onto the surface to prevent a skin from forming.