Soak the skewers totally submerged in water for at least 20 minutes to prevent them from burning.
Heat the oven to 450°F/230℃. Lightly spray or oil baking sheet or roasting pan to prevent the suya from sticking to the pan.
Peel roasted peanuts, and then grind them in a coffee grinder with skin on, until finely crushed, being careful not to grind them into a paste.
Mix garlic powder, onion powder, smoked paprika, white pepper, cayenne pepper, hot ground pepper, and bouillon (or Maggi) in a medium bowl. Add the ground peanuts to the spice mixture. Set it aside.
Pat the suya steaks dry with a paper towel. You want to have a completely dry steak before cooking. Slice the steak diagonally in medium-thin strips and place them in a bowl.
Add about 2 tablespoons of oil into the sliced beef, followed by 2-3 tablespoons or half of the suya spice mixture (set aside the rest of the spice rub). Mix everything until fully combined.
Cover the bowl with plastic cling wrap and marinate an hour.
When ready to cook, thread the strips onto the skewers, about four per skewer, making sure the slices of meat cover the skewers.
Rub the skewered steak strips on both sides with the rest of the spice mixture. Then line a roasting or baking sheet with foil and place the skewers on top.
Drizzle with oil and bake them for about 12-15 minutes.
Optional - For the last 3 minutes of baking, switch the setting from bake to broil to get a nice crisp brown on the outside.
You may also grill your suya beef. Brush the grill rack with oil and place the skewered meat on the rack. Brush them with oil and grill for a few minutes or until lightly charred, then turn and grill on the other side – about 3-5 minutes for each side, depending on the thickness of the meat slices.
Serve fresh from the oven or grill with onions and tomatoes.