For the goat cheese espuma, finely puree the goat cheese, sour cream, oil and spices with a stand/stick blender. Finally, add whipped cream and mix briefly until the consistency is viscous. Then strain through a fine sieve.
Pour into a 0.5 L iSi unit. Screw on an iSi cream capsule and shake vigorously. Chill for at least 30 minutes.
Serving suggestion: On nut or wholemeal bread.