Heat oil in a large Dutch oven over medium-high heat. Add leek, and sauté 5 minutes. Reduce heat to medium; add potato, 1/2 cup parsley, thyme, salt, and bay leaf. Cook 15 minutes, stirring occasionally. Add water, and bring to a boil. Cover, reduce heat, and simmer 20 minutes. Discard bay leaf.

Combine 2 cups potato mixture and tofu in a blender or food processor, and process until smooth. Return the puréed potato mixture to pan. Stir in 1/2 cup parsley and pepper. Cook for 5 minutes or until thoroughly heated.

Combine 1 cup water and broth in a Dutch oven; bring to a boil. Break pasta in half; add to pan. Bring mixture to a boil. Cover, reduce heat, and simmer for 8 minutes. Add shrimp to pan. Cover and simmer for 3 minutes or until shrimp are done; drain.

Melt butter in a large skillet over medium-high heat. Add mushrooms and pepper to pan; sauté 4 minutes or until moisture evaporates. Add flour, seasoning, and salt to pan; sauté 30 seconds. Stir in half-and-half; cook 1 minute or until thick, stirring constantly. Remove from heat. Add pasta mixture and parsley to pan; toss.

Boil the potatoes in a large pot for approximately 20 minutes or until a fork tender. Drain the potatoes and set aside to cool for approximately 5 minutes. Remove the skins from the potatoes (the potatoes will still be warm to the touch when you peel them), and place the skinned potatoes in a large bowl. Run a knife through the potatoes to coarsely chop them. Add the celery, pickles, onions, parsley, salt and pepper to the potatoes and toss. Fold in the mayonnaise to coat well. You’ll end up with a creamy potato salad that still has some soft chunks of potatoes.