Step 1

In a mini food processor, combine the onion, garlic, lemongrass and ginger and process to a paste. In a large skillet, heat the vegetable oil. Add the onion paste to the skillet and cook over moderately low heat, stirring occasionally, until browned, about 25 minutes.

Step 2

Add the ground coriander, sugar, ground fennel seeds, cumin, turmeric and salt to the skillet and cook over moderately high heat, stirring, until fragrant, about 1 minute. Scrape the spice paste into a bowl and let cool completely.

Step 3

In a large, shallow dish, coat the shrimp with the spice paste. Cover and refrigerate for at least 3 hours or overnight.

Step 4

Soak 30 bamboo skewers in water for 30 minutes. Light a grill. Thread 1 shrimp lengthwise onto each bamboo skewer and stretch each one out on the skewer. Grill over high heat for about 1 1/2 minutes per side, until the shrimp are nicely charred and just cooked through. Transfer the shrimp skewers to a platter, and serve immediately with the Garlic Peanut Sauce.