To make the crumble place flour, butter and sugar into a bowl, using your fingers rub the butter into the flour mixture until it combines, it should resemble wet sand.
Prepare cake as per packet instructions, once cake batter is in the cake tin, slice 4 pear halves and place on top of the cake batter.
Sprinkle crumble mixture over the cake and pear along with a handful of sliced almonds.
Bake in oven at 180° for 35-40 minutes or until a skewer inserted into the cake comes out clean.