Brittle egg sponge cake The brittle structure of this egg sponge cake makes for a different bite than our usual, soft egg sponge cake. Nice and crispy! Het gemak zelf ervaren? wenst u meer informatie bel 013-5385160. Brittle Our brittle, crispy egg sponge cake resembles the structure of a biscuit. If you like the crispness of biscuits, you should definitely try this one sometime.