Set circulator to 181°F (83°C). Cut the oyster mushrooms into one-inch cylinders.
Place the mushrooms, salt, pepper, and oil in a sous vide pouch and seal. Cook the mushrooms in a water bath for 2 hours or until tender.
Remove the pouch from the water and allow to cool at room temperature.
When ready to serve, score a hash mark into one flat side of the mushroom cylinder.
Add butter to a sauté pan over high heat and sear mushrooms, 2 minutes per side.
Set circulator to 181°F (83°C). Combine all of the ingredients for the parsnip purée into a sous vide pouch.
Cook in water bath for 2 hours.
After cooking, remove pouch from the water, open, and transfer into a blender.
While still hot, purée for 3 to 4 minutes until smooth.
Strain through a tamis mesh and set aside.
Spoon parsnip purée onto a plate. Arrange the mushroom “scallops” on top. Garnish with escarole and a small drizzle of olive oil.
