What I recommend is an entire food experience. Babies are sensory creatures. Choose your spice and introduce it to baby's many senses. Each time you introduce a new spice think of it as a sensory learning experience and do the following.
Sight and Sound: Since spices are so small and generally do not make much sound I've combined these two senses together. Get an empty jar of some sort that is clear like a plastic water bottle or an empty baby food jar. Put some spice in there with hard beans or rice. Then tape the top. Baby can use it as a home made rattle. Of course if you have the full version of herbs and spice baby can enjoy looking at them that way as well.
Smell: Put a dab of the spice on your finger, smell it. If it isn't too strong then hold about an inch away from baby's nose and allow baby to smell. Learning smells is a fun experience!
Touch: Put some of the spice in a bowl and let baby feel it. This will be fun for baby and perhaps even help the development and perfection of the pincher grasp. If your baby uses a pacifier this is the perfect time to let baby suck on it as it will help prevent the hand to mouth scenario. If baby does not then just be sure to keep a close eye on baby to make sure a handful of spice doesn't go into the mouth.
Taste: Mix the spice with one of baby's favorite foods and allow baby to taste it!
Here are some ideas of what foods and spices may work well together. The information was gathered from Wholesome Baby Foods.
Apple(Sauce): use cinnamon, nutmeg, allspice, vanilla, ginger
Pears: use ginger, cinnamon, a drip of vanilla or even mint
Bananas: use cinnamon, ginger, allspice, vanilla
Plain Yogurt : use with mint, cinnamon, nutmeg, vanilla, ginger, allspice, cardamom
Sweet potato: use with nutmeg, cinnamon and/or cardamom
Pumpkin: use with cinnamon, nutmeg, ginger and dash of vanilla
Carrots: use with basil & garlic - baked cinnamon carrots are yummy too.
Green beans: use with garlic powder
Mashed potatoes(white) : use with dill weed or garlic
Winter Squash (acorn, hubbard, butternut etc.): use with cinnamon, nutmeg, allspice, ginger
Pasta: use oregano, garlic, basil
Oatmeal or other cereals: use fruits, cinnamon & nutmeg, dash of vanilla
Rice (sweet) with cinnamon, nutmeg, dash of vanilla, cardamom, ginger
Quinoa (sweet): use cinnamon, nutmeg, dash of vanilla, cardamom, ginger for sweet
Quinoa (savory): use garlic powder, pepper, onion powder, basil, oregano and others
Chicken/Turkey with cinnamon and/or coriander
Chicken/Turkey with garlic powder and basil
Chicken/Turkey with lemon zest and pepper
Chicken/Turkey with basil & oregano
Chicken/Turkey with garlic and pepper
Chicken/Turkey with sage, rosemary and thyme
Beef with garlic and pepper
Beef with onion powder and pepper
Beef with Orange Zest"