Preheat oven to 180°C.

Place porcini in a heatproof bowl; cover with boiling water.

Place half the pine nuts on an oven tray; roast for 5 minutes or until fragrant. Cool in a large bowl.

Line two oven trays with baking paper. Spray one sheet of pastry with oil; top with a second pastry sheet, spray with oil then top with a third sheet. Repeat to make two stacks. Cut each stack in half length-ways; cut each half into thirds for a total of 12 pieces. Place pastry pieces on trays. Coarsely chop remaining nuts; sprinkle nuts and 1/4 cup of the parmesan on four of the pastry pieces.

Bake all pastry squares for 8 minutes or until browned lightly.

Meanwhile, heat butter in a large frying pan over medium-high heat; cook shallot, oyster and drained porcini mushrooms, stirring, until browned. Transfer to a large bowl with pine nuts.

Cook silver beet in the same pan until wilted slightly. Transfer to the large bowl; stir in ricotta, rind, currants and remaining parmesan until just combined. Season to taste.

Place four plain pastry pieces on serving plates; top with half the silver beet mixture, another plain pastry piece, remaining silver beet mixture then pine nut pastry pieces. Serve immediately.