Potato , Mushroom & Leek Croquettes - with greens & Shallot Vinaigrette

Ready in 40 minutes ... The Game plan ... While potatoes cook : Cook mushroom mixture ... While Croquettes cook : Make salad ........
8 ounces coarsely chopped peeled Yukon gold potato (optional any white potato)
4 ounces sliced cremini mushrooms
1/2 cup chopped leek
1 teaspoon fresh chopped thyme
Cooking spray
1/2 cup (2 ounces) shedded Gruyere cheese
1/4 cup (1 ounce) grated Parnigiano-Reggiano , divided
1/2 teaspoon kosher salt
1/2 teaspoon freshly ground black pepper
1 large egg yolk
1/3 cup all-purpose flour
1 large egg white
2 teaspoons water
1/2 cup panko (Japanese breadcrumbs)
1 tablespoon olive oil
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1) Place patato in pan ; cover with water . Bring to a boil . Reduce heat ; simmer 8 minutes or until tender . Drain. Press potato through a ricer or food mill into a bowl .
2) Place mushrooms , leek and thyme in a food processor ; pulse until finely chopped . Heat a large skillet over medium heat . Coat pan with cooking spray . Add mushroom mixture ; cook 6 min utes , stirring occasionally . Add mixture to potato . Add Gruyere , 2 tablespoons Parmigiano-Reggiano , salt , pepper and egg yolk ; stir until blended . Shape mixture into 8 (2-inch) round patties .
3) Place flour in a shallow dish. Combine egg white and 2 reaspoons of water in a shallow dish stirring with a whisk . Combine remaining 2 tablespoons Parmigiano-Reggiano and panko in a shallow dish . Dredge patties in flour . Dip in egg mixture , dredge in panko mixture . Heat a large skillet over medium-high heat . Add oil , whirl to coat . Add patties ; cook a minute on each side or until golden .
Serves 4 ( serving size 2 patties )
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For the Greens & Shallot Vinaigrette :
Combine 2 tablespoons olive oil , 2 tablespoons sherry vineger , 1/4 teaspoon black pepper and 1/8 teaspoon salt in a medium bowl . Add 6 cups salad greens and 1 sliced shallot to bowl ; toss gently.
Serves 4 ( serving size 1 -1/2 cup)