This variety of lavender is called lavandin, a cross between English lavender (L. angustifolia) and spike lavender (L. latifolia) cultivated in Spain and France.
The purple flower buds are used whole in tea blends, custards, cakes, muffins and in other baked goods. As a seasoning, lavender is a component of the classic blend herbs de Provence, which is commonly used in French cuisine to infuse flavor into roasted meats, grilled fish, vegetable dishes and soups and stews. Note that this variety of lavender contains a fair amount of camphor, which gives the flowers a mild pine-like flavor, so use it sparingly in cooking, as you would rosemary or other strong-flavored herb.