In a food processor, combine the red onion, scallions, garlic, ginger, curry powder, turmeric, cumin, salt, soy sauce, lemongrass, lime juice, coconut milk, peanut oil, and peanut butter. Purée until smooth.
2. Step
Divide the sauce between 2 small bowls. Add the chopped peanuts to one of the bowls and stir to combine. Cover with plastic wrap and refrigerate until ready to use.
3. Step
Pour the remaining sauce over the cubed beef in a medium bowl. Toss well to coat. Cover the bowl with plastic wrap and let marinate in the refrigerator for at least 2 hours, up 6 hours.
4. Step
Preheat the oven to 425°F (220°C). Line a 9-inch (23 cm) square baking dish with parchment paper.
5. Step
Thread the beef cubes onto skewers and set over the baking dish.
6. Step
Bake for 20 minutes, until the beef is seared and juicy.
7. Step
Serve the satay beef with the reserved sauce alongside.
