¾ cup thinly sliced leek, white and light green parts only
½ tsp kosher salt, divided
4 cups coarsely chopped cauliflower florets
1 ½ cups unsalted chicken stock, divided
¾ cup water
2 tsp chopped fresh thyme
¼ cup 2% reduced fat milk
1 ½ tsp butter
¼ tsp white pepper
1 package mushroom (of choice) caps
1 tsp lower sodium Worcestershire sauce
1 tsp sherry vinegar
2 tsp chopped fresh parsley
Heat a large saucepan over high heat. Add 2 tsp oil to pan and sauté leek 1 minute. Add 1/8 teaspoon salt. Cover, reduce to low and cook 5 minutes. Add cauliflower, 1 cup and 6 tablespoons stock, water and thyme. Bring to a boil; cover, reduce heat and simmer 7 minutes. Place cauliflower in blender and blend until smooth. Return to saucepan. Stir in remaining salt, milk, butter and pepper. Keep warm.
Thinly slice mushrooms. Heat a large skillet over medium-high heat. Add remaining 2 teaspoons oil to pan and sauté mushrooms 6 minutes. Add remaining stock, Worcestershire sauce and sherry vinegar. Cook 1 minute or until liquid is reduced and syrupy.
Spoon about 1 cup soup into each of 4 bowls and top each serving with about 2 tablespoons mushroom mixture.