Preheat the oven to 350°F and place the whole ears of corn, husks and all, directly onto a center rack and roast for 30 minutes.
Carefully remove the corn from the oven allow it to cool slightly then pull back the hot husks and silks.
Strip the kernels of corn from the cob and transfer them to a mixing bowl. Add the cilantro, red onion, roasted jalapeno, chile powder, and 1/3 cup of the cashew sour cream. Stir to combine and season to taste with salt. If the corn needs more cashew cream add it now until you reach the perfect creamy consistency. Set aside.
Preheat a grill pan over medium heat. Drizzle the avocado halves with fresh lime juice and brush lightly with olive oil. Gently place cut side down on the grill and cook for for 2-3 minutes. Season with salt to taste.
Fill each avocado half with the Mexican street corn and drizzle with hot sauce. Serve immediately.