Pour 350ml of beer into the base of a steamer.
Season the prawns with salt and pepper in a bowl and drizzle with olive oil.
Steam the prawns in a covered basket for 5 to 6 minutes while heating a griddle pan.
Toss the asparagus in olive oil and season with salt and pepper.
Grill the asparagus on the hot pan for 3 to 4 minutes until tender.
Bring the butter to a simmer in a saucepan.
Heat the lemon juice and vinegar in a separate pan until just boiling.
Place egg yolks and salt into a food processor and begin blending.
Slowly pour the hot lemon mixture and hot butter into the running processor until emulsified.
Serve two prawns and three asparagus spears per person topped with hollandaise.