Chop the shallots and tarragon in the mini bowl (4/5 pulses).

Put the resulting mixture in a small, thick-bottomed saucepan with the vinegar, salt and pepper. Reduce* to half its original volume over a low heat.

Pour the reduction into the mini bowl. Add the egg yolks and pulse 3 times.

Add the diced butter and pulse 5/6 times until the sauce reaches the right consistency.

Serve with grilled red meat.