Heat the olive oil in a skillet over medium heat, and saute the garlic until lightly browned. Place mushrooms in the skillet, and cook 5 minutes. Mix in asparagus, and cook 5 minutes, or until tender. Stir in the tomatoes. Season with salt and pepper. Reduce heat to low, and simmer 20 minutes.
Bring a large pot of lightly salted water to a boil. Place penne pasta in the pot, cook for 8 to 10 minutes, until al dente, and drain.
Mix the heavy cream into the skillet, and continue cooking 10 minutes, until sauce is thickened. Serve over the cooked pasta.
