Brush the portobello mushrooms with olive oil, then sprinkle with salt to taste. Place the mushrooms in a single layer on a wire rack on top of a baking sheet. Cook in the 425 degree oven for 5 to 10 minutes, or until they’re beginning to get tender. (The wire rack keeps the mushrooms from getting soggy. Timing will vary according to the size of the mushrooms.)
Remove the baking sheet from the oven and top the mushrooms with pizza sauce, cheese, and cherry tomatoes.
Return the mushrooms to the oven and bake for another 8 to 10 minutes, or until the cheese is melted. Sprinkle with fresh basil and serve.