Poached eggs with cheese sauce

Directions
Preparation:20min  ›  Cook:15min  ›  Ready in:35min 

1. Using a large, plain, round pastry cutter, stamp out a round from the centre of each slice of bread. Toast the rounds on both sides and use 30 g of the butter to spread them on one side. Divide the tomatoes equally among four heatproof plates, placing them on the side, and dot with 60 g of the butter. Place two rounds of buttered toast on each of the four plates and keep warm.
2. Melt the remaining butter in a small saucepan, stir in the flour and cook, without browning, on low heat for 1 minute. Gradually stir in the milk, season with the salt and pepper to taste and bring to the boil, stirring until it has thickened. Reduce the heat and continue to cook for 2–3 minutes longer. Add the grated cheese and stir until it has melted. Remove the sauce from the heat and keep it warm.
3. Fill a large frying pan with water, add the vinegar and 1/2 teaspoon of salt and bring to the boil. Break two eggs, each into a separate cup. Stir the water, then carefully tip in the eggs, one at a time. Cover and cook on low heat for 2–3 minutes, or until the whites are set. Lift the eggs out with a slotted spoon, drain them on paper towels and keep warm.
4. Cook the remaining eggs quickly in the same way and put one on each piece of toast. Spoon some cheese sauce over each egg and grill, in two batches if necessary, for 2 minutes, or until they are lightly browned. Sprinkle the tomatoes with chives and serve at once.