Place the shucked corn cobs in a large microwave-safe bowl with 3 tablespoons of water. Cover with a plate or microwave-safe lid and microwave on high for 3 minutes. The corn should be slightly tender but not fully cooked. Carefully remove and let cool for 5 minutes — the cobs will be hot and steamy.

Pat each cob dry with a kitchen towel. Trim a thin slice off both ends of each cob to create flat, stable surfaces.

Stand one cob on its end on a sturdy cutting board. Place a large sharp chef's knife across the top of the cob, centered. Press down firmly with both hands — one on the handle, one on the dull spine of the blade — and rock the knife down through the cob to halve it lengthwise. The par-cooked cob will give way much more easily than a raw one.

Lay each half flat side down and slice lengthwise again to create 4 ribs per cob. Repeat with the remaining cobs. You should have 16 ribs total.

Preheat the oven to 425°F. Line a rimmed baking sheet with parchment paper.

In a large bowl, whisk together the oil, smoked paprika, chili powder, garlic powder, salt, and pepper. Add the corn ribs and toss gently with your hands until evenly coated.

Arrange the ribs in a single layer on the prepared baking sheet, kernel side up. Bake for 18–22 minutes, until the kernels are deeply golden at the edges and the ribs have curled slightly. Start checking at 18 minutes — you want char, not burn.

While the corn roasts, whisk together the mayonnaise, sour cream, lime juice, grated garlic, and salt in a small bowl. Set aside.

Transfer the hot corn ribs to a serving platter. Drizzle generously with the elote crema (or serve the crema on the side for dipping). Sprinkle with cotija, Tajín, and cilantro. Serve immediately with lime wedges.