This is an excellent addition to any chinese style stir-fried vegetables. Very easy to make at home as well...
2 tsp whole black pepper/white peppercorns
4tsp whole anise seeds and or star anise
1/2 tsp whole cloves
1Tbsp whole fennel
(you may want use any or all of these spices in ground form if they are more conveniently available to you in that form.)
Put them in a spice/coffee grinder and grind them to a fine powder.
Add 1/2-1 tsp (or more according to your taste adn the quantity of food you are preparing) one or two minutes before taking your stir fry off the heat.