Pickerel with Potatoes & Tartar Sauce

INGREDIENTS & PORTIONS REQUIRED FOR THIS RECIPE:
• 4 skin-on pickerel Fillets (about 170 g each)  • 1 lb (450 g) mini potatoes
• 1 large egg  • 1 tablespoon (15 mL) Dijon mustard  • 265 mL grapeseed oil or vegetable oil
• Juice of 2 lemons  • ¼ cup (60 mL) minced drained capers  • ¼ cup (60 mL) minced gherkin pickles
• ¼ cup (60 mL) minced shallot  • ¼ cup (60 mL) chopped fresh flat-leaf parsley  • 1 teaspoon (5 mL) minced garlic
• Kosher salt and freshly cracked black pepper  • 2 tablespoons (30 mL) unsalted butter
• 1 lb (450 g) green beans, trimmed  • Fresh oregano