the top press plate and begins applying pressure on the dough slice through the top press plate the slice is squeezed with consecutive slow bursts of downward movement to allow the dough sufficient time to soften under the heat and expand without tearing or creating air pockets referring now to fig9 d as the top press plate reaches its lowermost position the dough fills out the cavity between the plates and takes on the flat circular shape with slightly raised edges in this position with the dough slice in full contact with the press the par baking process begins but as the cavity is fully sealed there is a great increase in pressure between the plates referring now to fig9 e in order to limit the rise in pressure after a short delay the pushing plate begins to move back up in timed small spurts initially due to the pressure the top press plate is pushed up against the pusher plate referring now to fig9 f as the plates continue to rise the seal between the plates is eventually broken and some of the pressure is evacuated causing the top press plate to fall back onto the pie continuing the par baking process the exact point when the top press plate falls back onto the pie can be at any of a range of different positions the pushing plate needs only to retract up to a pre determined upper limit midpoint a where the seal between the plates is certain to have been broken and the pressure relieved accordingly the shoulder screws 218 must be of sufficient length to allow the press plate to fall back onto the pie when the pressure drops referring now to fig9 g h with the press plate on the pie.