Mixed salad greens, lightly dressed with your favorite vinaigrette
Fill the SousVide Supreme up to the fill line.
Arrange 4 empty ramekins on a baking rack in the water oven. Fill them with water. Check that the water in the bath reaches half way up the side of the ramekins. Add more water if needed.
Remove and dry the ramekins and grease each one with the melted butter.
Preheat the SousVide Supreme to 185°F (85°C)
Heat the olive oil in a medium sized saucepan.
Add the diced onions and saute until soft and golden (about 10 minutes).Take off the heat and leave aside to cool.
Put the eggs and cream into a bowl; add a pinch of salt and pepper and the chopped chives and whisk the mixture together.
Divide the cooked onions among the ramekins and pour the egg mixture on top of the onions; top with the sliced asparagus tips and feta, dividing equally among the four.
Carefully place the ramekins into the water oven on the raised baking rack, taking care not to get any water into the ramekins. Cover the ramekins with squares of foil, slightly tented to prevent condensation from dripping into them.
Leave to cook in the water bath for 45 minutes.
Remove the foil and then the lift out the ramekins with a kitchen glove or tongs.
Allow the flans to cool for a few minutes on a wire rack.
You can serve the flans straight from the ramekins, or, you can slide a knife around the edges of the flan and carefully invert it onto a plate.
Garnish with some freshly grated Parmesan and serve with a green salad.