Asparagus and morel tart

Method

1. For the pastry case: preheat the oven to 180C/gas 4.

2. Roll out the pastry to 6mm thick and cut into 2 rectangles.

3. Score a line 5mm in from the edge, all the way round, to form a border on each rectangle.

4. Brush the pastry with the egg yolk, place on a baking tray and bake in the oven for 10-15 minutes, until crisp and golden brown. Remove from the oven and set aside to cool. When cool enough to handle, cut off the top layer of pastry from the centre of each rectangle to make a lid.

6. For the asparagus and morels: steam or boil the asparagus for 2-5 minutes, depending on the thickness, until just tender.

7. Melt a knob of butter in small frying pan over a medium heat and fry the morels for 3-4 minutes or until soft.

8. For the mousseline sauce: pour the vinegar and vermouth into a small saucepan with the shallot, half the tarragon, bay leaf and peppercorns. Place over a high heat and boil until reduced to two teaspoons in volume.

9. Strain through a sieve and set aside to cool.

10. Melt the butter in a saucepan over a medium heat then simmer for 5 minutes. Remove from the heat and leave to cool. Once it has cooled down, carefully pour the top layer of clarified butter into a clean bowl, leaving behind the white solids that will have sunk to the bottom. Discard the white solids.

11. Tip the egg yolks and half of the vinegar reduction into a heatproof bowl set over a pan of barely simmering water (make sure the bottom of the bowl doesn’t touch the water as the heat would be too fierce). Whisk continuously until the mixture is thick and frothy.

12. Once it reaches this stage, gradually trickle in two thirds of the clarified butter, whisking continuously.

13. Taste the sauce and add more vinegar reduction if necessary, then whisk in the remaining butter and season with salt and freshly ground white pepper.

14. To serve, pile the warm asparagus and morels into the pastry case and top with the pastry lid. Fold the whipped cream and remaining tarragon into the sauce and pour around the tart