Step 1

In a medium Dutch oven or other heavy pot over medium heat, melt the butter. Add the thyme, shallots, and garlic and cook, sweating the shallots, for 3 to 5 minutes, until fragrant and softened. Add the wine, bring to a simmer, and reduce for about 10 minutes, until almost completely evaporated. Remove and discard the thyme sprigs. Sprinkle the flour over the vegetables and stir well to coat. Continue to cook, stirring, for 5 to 7 minutes, until the flour smells nutty and has begun to take on a hint of light tan.

Step 2

While stirring constantly, slowly add the milk and cream. The mixture will seize up and the flour will clump for a moment but will ultimately reincorporate and the mixture will become smooth. Bring to a gentle simmer, continuing to stir to avoid scorching, and cook until the mixture thickens to the consistency of thick gravy. This will take about 6 minutes. Season with the salt and pepper to taste.

Step 3

TO FREEZE: Spread the béchamel on a rimmed baking sheet and let cool to room temperature. Portion and transfer the béchamel to freezer-safe containers, such as vacuum pouches, quart-size zip-top plastic bags, or pint-size lidded plastic containers. Label and date and freeze for up to 3 months.

Step 4

TO THAW: Pull the béchamel out of the freezer and thaw it in the refrigerator for 24 hours, or put the packaged béchamel in a into a larger bowl or other vessel, or even a plugged sink, and run a slow steady trickle of cold water over it until it thaws.

Step 5

TO REHEAT: If you used vacuum pouches, reheating from frozen using the sous vide method works well. Set the sous vide water bath to 145°F and drop in the pouch. It will take about 1 hour to reach temperature, depending on the volume. Otherwise, thaw first, then transfer to a saucepan and reheat on the stove over medium heat, stirring frequently, until it begins to gently simmer.