Using a mandolin, slice potatoes as thinly as possible lengthwise
Place in large bowl and pour cream over potato slices; toss to coat evenly and prevent oxidation
In large skillet heat 1/4 cup butter over medium-high heat until bubbling; stir in chopped mushrooms and cook, stirring often, until all moisture evaporates and mushroom mixture starts to caramelize.
Remove from heat and cool slightly; stir in parsley and salt and pepper, to taste. Cool completely. Hold.
Assembly and Cooking:
Line two 8x5-inch loaf pans with foil, allowing extra foil to wrap over top edges. Thoroughly butter foil lining.
Shaking off excess cream from slices, remove slices in cream from bowl and line bottom of each foil-lined pan with a double, shingled layer of potato slices. Spread 1/4 cup of mushroom mixture evenly over each layer of potato slices. Repeat 2 more times, ending with a final potato layer on top (there will be 4 layers of potatoes and 3 mushroom layers in each pan).
Cut a piece of foil for each pan slightly larger than the pan. Butter the shiny sides of these pieces and lay them on top of the potato layer in each pan, to completely cover. Fit another pan on top of this foil layer inside each pan and weight it with a brick or heavy, oven-proof object.
Bake in 375°F convection oven for 1 1/2 hours. Remove from oven and let cool to room temperature.
Refrigerate 8 hours or overnight, with weights still in place.
Remove from refrigeration and take out of pan. Remove foil. Put into desired shapes before ready to prepare for service.
For each serving; In small skillet heat 1 1/2 teaspoons of oil over medium-high heat; place cut piece (s) of pavé in a pan and sauté each side 3-4 minutes to heat through and brown each side. Finish in 375°F oven for 10 minutes until heated through. Serve each plate with 2 tablespoon fresh tomato coulis, a drizzle of 1 teaspoon red wine reduction and several dots of herb oil. Blot excess oil of pavé before plating on top of the plate.