In a large skillet, heat 1 tbsp. butter over medium heat and add the leeks. Cook until tender. Add the garlic and artichokes. Cook for 5 min. Add the broth, reduce heat to low and simmer 10 min.
Blend the sauce components using a immersion blender or high speed blender. Stir in the heavy cream and set aside.
Add the other tbsp. butter to a large skillet and add the mushrooms. Cook until they are reduced and browned. Add the truffle salt.
Spread the pizza dough onto a grill pan. Prick the dough lightly with a fork. Brush 1 tsp. of the truffle oil on the dough. Cover and grill until the dough is cooked through, about 5-7 minutes.
Assemble the pizza: spread the leek & artichoke puree over the crust. Add the mushrooms and arugula. Drizzle with truffle oil and serve!