Source : Merry's Kitchen
Basil, Lemon (daun kemangi): A fragrant, lemon-scented herb added at the last minute to keep its flavor, or used as a grarnish. Although the flavor will be different, you can use another type of basil. 
Candlenut (tingkih/kemiri): A round, cream-colored nut with an oily consistency used to add texture and a faint flavor to many dishes. Substitute macadamia nuts or raw cashews.
Cardamom (kapulaga): About 8-12 intenselu fragrant black seeds are enclosed in strawcolored, fibrous pod. Try to buy the whole pod instead of cardamom seeds or powder for maximum flavor, and bruise lightly with the back cleaver to break the pod before adding to seasonings.
Celery (seledri): The celery used in Indonesia is somewhat different form the celery used in the Western world. It has a very slender stems and particularly pungent leaves. It is often referred to as "Chinese celery" abroad and is used as a herb rather than a vegetable.
Chilies (cabai, also called cabe or lombok): There are several types of chili pepper used in Indonesia. One thing that is important about chili pepper, the amount of heat increases as the size of the chili pepper diminishes. Green chilies are the unripe fruit, and have a flovor different from red chilies. Fresh, finger-length red chilies are the most commonly used. Dried chilies also used in some dishes and they should be torn into pieces and soaked in hot water to soften before grinding or blending. Hottest of all chilies are the tiny fiery bird's-eye chilies (cabe rawit). To reduce the heat of the dish while retaining the flavor, remove some or all the chili's seeds.
Cinnamon (kayu manis): A thick, dark brown bark of a type of cassia. Do not substitute with ground cinnamon if you can.
Cloves (cengkeh): A small, brown, nail-shaped spice. Whole cloves are frequently used to flavour cooking liquids for simmering fish, poultry or meat.
Coconut (kelapa): The grated flesh of the coconut is frequently added to food. It can also be squeezed in water to make coconut milk. To make fresh coconut milk, put 2 cups of freshly grated ripe coconut into a bowl and add 2 cups of lukewarm water. Squeexe and knead the coconut thoroughly for 1 minute, then strain thorugh cheesecloth into a bowl to obtain thick coconut milk. Repeat the process with another 1 cup of water to obtain thin coconut milk. Combine both for the coconut milk. Coconut milk can be frozen; thaw and stir thoroughly before use. The best substitute for fresh coconut mik is instant coconut powder. Combine this with warm water as directed on the packet. For richer, creamier flavor required for desser and cakes, use canned (unsweetened) coconut cream.
Coriander Seeds (ketumbar): Small straw-colored seeds with a faintly orange flavor. Whole seeds are usually lightly crushed before use.
Cumin (jintan): use sparingly as it has a strong smell.
Cup Leaves (daun mangkok): The shape of the leaf is like a cup. It's also known as tapak leman (Nothopanax scutellarium) and it usually used to cook stew dishes. A good substitute is curly kale.
Garlic (bawang putih): The cloves of garlic in the Western countries are considerably larger. Adjust the amount to suit your taste.
Ginger (jahe): This pale creamy yellow root is a very important ingredient for Indonesian cooking. Always scrape the skin off fresh ginger before using, and never substitute powdered ginger as the taste is quite different. Ginger can be stored in a cool place for several weeks.
Kencur: It is sometimes known as lesser galangal. This ginger-like root has a unique, champor flavor and should be used sparingly. Wash it and scrape off the skin before using. Dried sliced kencur or kencur powder can be used as a substitute. Soak dried slices in boiling water for approximatley 30 minutes; use ½-1 tsp. of powder for 1-inch fresh root.
Laos (lengkuas): Sometimes is called galangal, this is a member of the ginger family and it has a very tough but elusively scented root that must be peeled before use. Substitute slices of dried laos (soaked in boiling water for 30 minutes) or powdered laos (1 tsp = 1 inch).
Lemongrass (serai): This is an intensely fragrant herb that is used for soupd, seafood and meat dishers and spice pastes to produce lemony flavor. Cut off the roots and peel off the hard outer leaves, use only the tender bottom portion (6-8 inches).
Lime: There are several types of lime used in Indonesia. The most fragrant one is called kaffir lime (jeruk purut). Kaffir lime has virtually no juice, but the double leaf is often used whole or very finely shredded, while the grated skin is occasionally used in cooking. The picture on the right shows Kaffir lime. The round yellow-skinned limes which size is slightly larger than a golf ball (jeruk nipis) and small, dark green limes (jeruk limau) are used for their juice. If limes are not available in your area, you can subsitute it with lemon.
Nutmeg (pala): Always grate whole nutmeg just before using as the powdered spice quickly loses its fragrance.
Palm Sugar (gula jawa): Juice extracted from the coconut flower or aren palm is boiled and packed into molds to make sugar with a faint caramel taste. If palm sugar is not available, substitute with soft brown sugar. To make palm sugar syrup, combine 2 cups of chopped palm sigar with 1 cup of water and 2 pandan leaves. Bring to a boil, simmer for 10 minutes, strain and store in refrigerator.
Pandan Leaf (daun pandan): The fragrant leaf of a type of pandanus sometimes known as fragrant screwpine, this is tied in a knot and used to flavor dessert and cakes.
Peanuts (kacang tanah): Used raw and ground to make suace, or deep fried and used as a garnish or condiment.
Pepper (merica): Both black and white eppercorns are crushed just before usel ground white pwpper is also used on occasion.
Salam Leaf (daun salam): A subtly flavored lead of the cassia family, this bears no resemblance whatsoever to the taste of a bay leaf, which is sometimes suggested as a substitute. If you cannot obtain dried salam leaf, omit altogether.
Shallots (bawang merah): Widely used in Indonesian cooking, pounded to make spice pastes, sliced and added to food before cooking, and sliced and deep fried to make a garnish.
Shrimp Paste (terasi): This ingredient has a strong fragrance; it is always cooked before eating, generally toasted over a fire before being combined with other ingredients. The color of this ingredient range from purplish pink to brownish black.
Slaked Lime (kapur sirih): A paste obtained by grinding sea shells in a little liquid. This is the lime which is chewed with betelnuts, gambir and tobacco.
Soy Sauce: There are two types of soy suace that are used in Indonesian cooking, thick soy sauce (kecap manis), and the thinner, more salty thin soy sauce (kecap asin). If you cannot obtain sweet soy sauce, use the dark black Chinese soy sauce and add brown sugar to sweeten it.
Tamarind (asem/lunak): The dark brown pod of the tmarind tree contains a sour fleshy pulp, which adds a fruity sourness to many dishes. Packets of pulp usually contains the seeds and fibers. To make tamarind juice, measure the pulp and soak it in hot water for 5 minutes before squeezing it to extract the juice, discarding the seeds, fiber and any skin.
Turmeric (kunyit): An essential root in Indonesian cooking, usually sold in dried or powdered form in the US and Europe. It imparts its yellow color and pungent taste to many dishes. If you can buy fresh turmeric, pick roots that are da
