You can use fresh or dried lavender flower buds but ensure you use the right sort! Squeeze a few of the flower buds between your fingertips and it must be a sweet lavender scent.
If it smells like mothballs or camphor, do not use it. It will leave a bitter taste and spoil your cooking.
Cooking lavenders belong to the Lavandula angustifolia species. Some of the favourite varieties are ‘Avice Hill’, ‘Munstead’, Egerton Blue’.
TALGA can put you in touch with a grower supplier of culinary lavender.