Preheat oven to 500°F with a rack in the center. If you have a pizza stone, preheat it on the center rack. (If not, you can use an overturned half sheet pan.)
In a 12-inch nonstick frying pan, melt butter over medium heat. Add mushrooms, garlic and salt and raise heat to high. Toss mushrooms to coat with butter. Cook for 5 to 10 minutes, until they are beginning to brown in spots and have significantly reduced in volume. Add wine and cook until all the liquid is gone. Stir in heavy cream, asparagus and tarragon, reduce the heat to simmer briskly, and cook for an addition couple of minutes, until the cream has thickened to coat the vegetables without dripping.
Rub pizza dough with olive oil and divide into two equal portions. Stretch each portion into a 12-inch round. I like to place each round on a piece of parchment to make transfer to and from the oven much easier. Top each with half the vegetable mixture, half the gruyere and half the pecorino. Bake for about 1o minutes, until dough is crisp on the underside and cheese is bubbly. (I bake one pizza at a time, putting the second one in the oven as we sit down to eat the first.) Sprinkle with parsley and pepper. Cut into slices and serve.