There are two types of "hedgehogs" you can make using flour, water, cocoa powder and salt. One is an Australian dessert known as a "Chocolate Hedgehog." The other is a non-edible hedgehog, using the ingredients to make a play dough. Try your hand at both versions.
Melt the butter and sugar in a saucepan over medium-low heat, whisking to combine and prevent the butter from burning.
Remove the butter mixture from the heat and allow it to cool completely.
Whisk the egg, 1/4 tsp of salt, 1 tsp of vanilla extract, 1/2 cup of cocoa powder and 1/4 cup of flour into the mixture until thoroughly combined. Fold in the crumbled cookies.
Line a baking pan with waxed paper. Spread the hedgehog mixture into the pan and smooth the top flat with a spatula. Chill the pan in the refrigerator for two hours or until set.
Combine 2 cups of icing sugar, 1/2 cup of cocoa powder, 1 tbsp of melted butter and 1/4 cup of warm water in a bowl and whisk to form a thick paste for the icing.
Spread the chocolate icing over the "hedgehog" in the baking pan. Cut into square or rectangular pieces and serve.
Mix together 1-1/2 cups flour, 1/2 cup cocoa powder, 1 cup of salt and 3/4 cup of warm water in a bowl until a soft dough forms; add more flour if necessary.
Shape the dough into an oval shape. Flatten the bottom portion of the oval on a table or other flat surface.
Insert slivered almonds or spaghetti pieces into the back of the oval to completely cover it with "hedgehog spines."
Pierce the front of the oval with two whole cloves to make the eyes of the hedgehog.
Let the salt dough hedgehog harden overnight.