Preheat the oven to 165°C. Line a buttered baking pan with a layer of butter puff, allowing the sides to come out and over the sides. Chill until required.
Melt the butter with the olive oil and cook the garlic for 20 seconds, then add in the sliced onions and picked rosemary leaves. Cook until lightly golden then set aside to cool.
Combine in a bowl the crème fraiche, parmesan, cooked onions and seasoning. Slice the peeled potatoes thinly using a mandolin or a V-slicer. Place into the crème mixture and
Place the potatoes in tight layers into the puff pastry lined pan until it is 4 cm high. Press down lightly, then top with the second puff pastry sheet, trimming to form a neat fitting top sheet. Brush all the edges with a little of the beaten egg and fold over the bottom sheet to close the tart.
Make several cuts into the top, brush with the egg and place into the oven. Bake for 1 hour or until golden brown, crisp and the potatoes are tender (test with a metal skewer).
Place the tomatoes into a small baking pan with a little olive oil and seasoning. Roast at 180°C for 5 minutes, remove and set aside.
Heat a pan, add a little olive oil and place in the seasoned snapper fillets skin side down. Hold them down for 1 minute to keep the skin flat, and then place into an oven (unturned) set at 200°C for 4 minutes, or until just cooked.
Remove from the oven, remove the fish and wipe out the pan with a little kitchen paper. Quickly add in the butter and lemon juice and stir to combine. Add in the chopped dill and season well.
Present the snapper with a slice of potato, the trussed tomatoes, a spoon of peas and finish with a nastursham leaf and a little sauce.