Remove puff pastry from freezer so it can soften slightly while you cook the onions. Thinly slice the white and light green parts of the leeks or spring onions. Melt butter in a large sauté pan, add leeks or onions and cook over low-medium heat, stirring often, 30–40 minutes or until soft and golden.
Add cream, 1 tablespoon each chopped fresh herbs (reserving remainder for garnish). Season with salt and pepper. Stir and simmer over low heat, 20 minutes. Remove from heat and set aside (or refrigerate up to 1 day).
Preheat oven to 425°. Roll out puff pastry sheet on a floured surface to ¼-inch thickness. Cut into 4 equal rounds using a large biscuit cutter or 4-inch inverted bowl. Place puff pastry rounds onto baking sheet lined with parchment paper. Prick each pastry with a fork to prevent uneven cooking. Whisk 1 egg with milk to create an egg wash, and brush lightly onto pastry.
Divide onion mixture onto pastry rounds and top each with goat cheese. Bake for 25 minutes, or until golden brown. (If pastry rises unevenly during cooking, push down gently with a fork while still warm.) Set aside in a warm place.
Fill large saucepan with water, add white vinegar and bring to a simmer. Crack eggs into four individual dishes, taking care not to break the yolk. Slide eggs, 1 at a time, into simmering water. Gently cook each egg until desired doneness, or about 4 minutes for a slightly runny yolk. Remove with a slotted spoon and pat dry.
To serve, place each egg atop a warm onion tart, sprinkle with remaining chopped herbs and enjoy.
WINE PAIRING—Domaine de Martinolles ‘Le Berceau,’ Blanquette de Limoux, France. Sparkling wine is perfect with fresh farm eggs, especially this choice from the southwest of France. It’s rich and creamy like a fancy Champagne but with a lithe freshness that is unique to Limoux and its indigenous grape, Mauzac. Fine bubbles will do a great job of scrubbing your palate, while flavors of crisp green apple and buttery brioche meld perfectly with the yummy fresh tart. —Eric Taylor, Bottles Fine Wine & Spirits
Recipe by Executive Chef Derek Jolie, Blackstone Caterers, Middletown