Œufs aux oignons (simplified variant)

Ingredients

• 4 whole hard boiled eggs (Already hard boiled; if not yet cooked, place eggs in cold water, bring to a boil, then simmer for 10 minutes and cool completely in cold water before peeling.)
• 1 teaspoon butter (Used to lightly grease the baking dish so the eggs do not stick.)
• 8 small portions (one per egg half) maître d'hôtel butter, prawn butter, or any fancy compound butter (Use whichever flavoured butter you have available. Maître d'hôtel butter is a classic herb butter made with parsley and lemon; prawn butter is made by blending cooked prawn shells with butter. Leftover compound butter from a previous meal is entirely appropriate and encouraged by the original recipe.)

Instructions

1. 1Preheat your oven to 200 °C (180 °C fan / Gas Mark 6). This ensures the eggs heat through quickly without drying out once they go in.
2. 2Using a sharp knife, cut each of the 4 hard boiled eggs cleanly in half lengthways (from tip to base). A sharp, wet knife gives the cleanest cut. You will now have 8 egg halves.
3. 3To help each egg half stand upright on the dish without rocking (in the style of œufs farcis — stuffed eggs), use a small sharp knife to shave a very thin sliver off the rounded base of each egg white half. Remove only as little as needed to create a flat, stable base. Take care not to cut into the yolk. If any yolk crumbles slightly, simply press it back into place gently.
4. 4Using your fingertip or a pastry brush, lightly coat the surface of a flat ovenproof dish with the teaspoon of butter. Stand each trimmed egg half upright, cut-side facing up, in the buttered dish. Space them so they are not touching one another.
5. 5Place the dish in the preheated oven and bake for 8 to 10 minutes, until the egg halves are thoroughly heated through. They should feel hot to the touch and may show a very light golden tinge on the yolk surface. Do not overbake — the goal is hot eggs, not rubbery ones.
6. 6Remove the dish from the oven immediately. Working quickly, place a small portion of your chosen fancy butter — maître d'hôtel butter, prawn butter, or any compound butter you have to hand — on top of each hot egg half, centred over the yolk. The residual heat of the egg will begin melting the butter into a glossy, flavourful cap as you bring the dish to the table. Serve at once on the dish, while the butter is still melting.