For the walnut caramel slices, place all the ingredients for the shortcrust pastry in a bowl and mix with a dough hook or mix on a work surface and quickly work into a shortcrust pastry. Cover with plastic wrap and let rest in the refrigerator for about 2 to 3 hours.
Divide dough in half and roll out 2 sheets about 16 x 40 cm in size, 3 mm thick (or to the size of the baking sheet). The baking sheet should have a high edge so that the nut mixture cannot escape.
For the nut mixture, put the sugar, whipping cream, honey, glucose and butter in a saucepan and heat to 115-120° C, stirring constantly. Remove from the heat, mix in the walnuts and allow to cool.
Place the overcooled mixture on one shortbread sheet and cover with the second shortbread sheet. Prick the surface several times with a fork to allow steam to escape and to prevent the pastry surface from tearing. Brush with beaten egg and bake the walnut caramel slices in the preheated oven at about 165 to 175 °C for about 18 minutes until light brown.
Variation: You can add some cinnamon to the nut mixture.