I am thinking of something like infiltration or adulteration, but for food. For example consider these sentences that should be compatible with the word being sought (as different parts of speech, of course):
The food at the restaurant tasted so good that it seemed like the chef _______ it with crack.
Even _______ the cake from this recipe with a small additional amount of sugar made it taste too sweet to be palatable.
The cookies were _______ with a small amount of chocolate and this made them absolutely irresistible.
I suppose the word “lace” would work, but I am looking for something with less of a negative connotation.