Place halved baby potatoes in a large pot and cover with cold salted water. Bring to a boil over medium-high heat, then reduce to a gentle simmer. Cook for 15-18 minutes until fork-tender but not mushy. You want them to hold their shape when mixed with the other ingredients. Drain thoroughly and let cool for 10 minutes.

While potatoes cool, heat a dry skillet over medium-high heat. Add corn kernels and cook for 3-4 minutes, stirring occasionally, until lightly charred and fragrant. This step adds that essential smoky street corn flavor. Set aside to cool.

In a large mixing bowl, whisk together mayonnaise, Mexican crema, lime juice, chili powder, and smoked paprika. The mixture should be smooth and well-combined. Taste and adjust seasoning with salt and pepper.

Add the cooled potatoes and charred corn to the bowl with the dressing. Gently fold everything together using a large spoon, being careful not to break the potatoes. Add diced jalapeño and half the cilantro, mixing until evenly distributed.

Transfer to a serving bowl and top with crumbled cotija cheese and remaining fresh cilantro. Give it a final sprinkle of chili powder for color and extra flavor. Serve immediately or chill for later.