Place a Plexiglas frame of the same external dimensions as the one used for the Demerara sponge on top of that frame. It should be .5 cm / .25 in deep.
Transfer the frozen crème brûlée into the frame on top of the sponge. Trim any excess from the top of the crème brûlée with a hot slicing knife so that it is flush with the top of the frame. Place another Plexiglas frame on top of the crème brûlée, of the exact dimensions throughout (width, length, and depth).
Place them in the freezer.
Churn or pacotize the blackberry sorbet and pour into the prepared frame. Even out the top so that it is flush with the frame. Freeze to harden. Place another frame of the same dimensions as the ones used for the blackberry sherbet on top. So far there should be 3 layers: sponge, brûlée, and blackberry sorbet, and there are 4 frames on the sheet pan.
Churn or pacotize the crème fraîche ice cream and pour into the prepared frame. Even out the top so that it is flush with the frame. Freeze to harden.
Once hardened, remove all of the frames from the cake by using a paring knife to cut around the inside border (make sure not to cut through the nonstick rubber mat).
Place a cutting board lined with an acetate sheet in the freezer.
Transfer the cake carefully to the lined cutting board. Freeze.
Cut 2 entremets from this cake using a long thin slicing knife. Have a hot water bath on hand to dip the knife into before each cut. Always dry the hot knife with a clean paper towel after dipping it in the water.
Trim one of the long borders of cake, then one of the short borders. Measure 17.5cm / 7in twice on the straight long border. Score the cake where the measures are with the tip of the knife.
Measure 10cm / 4in on the straight, short border twice. Score the cake where the measures are with the tip of the knife.
Using a knife, score the cake where it needs to be cut. Dip the knife and make the necessary cuts. There should be 2 rectangles 10cm / 4in by 17.5cm / 7 in. Discard the trim and freeze the cutout cakes for 10 to 15 minutes.
Pour the glaze on the surface of both cakes. Only a small amount is needed, just enough to cover the surface. Be careful not to let the glaze trickle down the sides of the cake. Use a small offset spatula to push the glaze across the cake’s surface.
Garnish each cake with 3 macarons, 5g / .18oz of toasted Sicilian pistachios, and 3 blackberry raisins.
Return to the freezer or temper for 10 to 15 minutes before serving.