Pekin duck, red miso, lemongrass 'mousseline'

Directions

1. Prepare the sauce (this can be done 1 day in advance): bring the beef stock to a boil and reduce by about 1/3.
2. Add a few spoonfuls of the stock to the miso to make a slurry, mix well, and stir back into the stock. Cook 5 minutes, making sure the mixture doesn't come to a boil.
3. Strain, weight, and measure 0.5% xanthan gum. Blend with an immersion blender and reserve in the refrigerator until needed.
4. Prepare the lemongrass mousseline: saute the baby leeks, lemongrass, and ginger in butter for 5 minutes, taking care not to brown. Season with salt.
5. Add the cream, bring to a simmer, and turn off the heat. Cover and let infuse for 30 minutes.
6. Strain the cream, whisk or blend in the xanthan gum, transfer to a whipping siphon and charge twice, shaking well. The gas acts as a preservative so this can be done in advance without loss in quality. Reserve in the refrigerator, and keep in a warm water bath during service until needed.
7. Prepare the duck: season the duck breasts with salt and vacuum pack. Cook sous vide at 134F for 1 1/2 hours.
8. To serve: warm the sauce in a pot on the stove. Remove the duck breasts from the bag onto a paper towel, discarding any juices. Heat a skillet with a very small amount of oil on medium heat, then add the duck skin side down to render out some of the fat and crisp. Traditionally duck skin is scored in a checker pattern, but I chose to omit that for this presentation. Use a blowtorch to accelerate searing or get any spots that are missed.
9. Flip the duck breasts and cook another 30 seconds.
10. Remove the seared duck to a paper towel and cut to serving portions.
11. Spoon a streak of sauce onto a place and place a portion of duck on top. Top with a pinch of Maldon salt. Pipe a small dollop of the lemongrass mousse onto a plate to check consistency; shake more to firm up if needed. Pipe a dollop of lemongrass mousse on each plate next to the duck and serve.