How to Make It
In a medium saucepan, melt 1 tablespoon of the butter. Add the leeks and garlic and cook over moderate heat, stirring occasionally, until softened, about 5 minutes. Add the stock and bring to a boil. Whisk in the quinoa and cook, stirring occasionally, until tender and porridge-like, about 25 minutes. Stir in the remaining 2 tablespoons of butter and season with salt and pepper; keep warm.
In a large cast-iron skillet, heat 1 tablespoon of the olive oil until shimmering. Add the pumpkin seeds and cook over moderate heat, stirring, until golden, 2 minutes. Transfer to a paper towel–lined plate; let cool.
Wipe out the skillet. Add the corn and cook over moderately high heat, turning, until charred, 10 to 12 minutes. Cut the kernels off of the cobs and transfer to a large bowl. Stir in the basil, cilantro and scallions and season with salt and pepper.
Wipe out the skillet and melt the butter in the remaining 1 tablespoon of oil. Season the shrimp with salt and pepper and cook over moderate heat, turning once, until just cooked through, about 3 minutes.
Spoon the quinoa grits into shallow bowls and top with the grilled corn, shrimp and pumpkin seeds. Garnish with chile powder and cotija cheese and serve with lime wedges.