Leon's Chocolate Brownie cake with secret spinach and melted chocolate on top

I tried this at first for Leon's 11th birthday traktatie at school. Speciale Onderwijs are more flexible about healthy traktaties as a class full of autistic children is usually a fussy one. I had done this recipe once before we moved to NL, but it was a good four years ago. I wanted to do something where he literally has no idea there is a cup of grated carrots and a cup of pureed spinach involved. He probably never will, at least until he's a good bit older.

This version is designed to be ideal for kids parties, you can substitute the milk chocolate for plain and the white sugar for soft brown for a more grown up twist. 

For the Sandwich cake version double what's here in this recipe and divide between two round silicone baking moulds. 

I like silicone as they come out beautifully and so easily, as well as being a doddle to clean.

The original recipe is pinched from Lorraine Elliot, who pinched it from Jessica Seinfeld. I changed it a bit and have converted it to grams.

I used frozen spinach puree, but if you need to use fresh, you can puree baby spinach as is, or remove stems for fresh spinach.

Ingredients

• 1/2 cup (25g) grated carrots (original used puree where you steam the carrots then puree, but it worked fine with grated or very finely chopped in a processor).
• 1/2 (115g) cup fine puree frozen spinach - well thawed, I microwaved directly before using, doesn't matter if it's a bit warm as it mixes better with the melted chocolate.
• 100g bar of Belgian/Dutch milk chocolate - yeah, use the good stuff!
• 1/2 cup/ 225g sugar - I used just white sugar, but orignal used soft brown 
• 1/4 cup/25g unsweetened cocoa powder (Droste)
• 2 tbsp/30g unsalted butter
• 2 tsp vanilla extract
• 2 large organic/free range egg whites
• 100g Self raising flour
• 1/2 tsp baking powder
• 1/2 tsp salt

For the topping:

• 100g bar of belgian/dutch milk chocolate

I used hazelnut chocolate spread for the middle of the sandwich, but a more grown up version would work beautifully with sour cream or mascarpone cheese.

Equipment

• 20cm x 20cm square baking dish or a 20x30cm rectangular dish works just as well 

or

• Two 25cm round silicone baking moulds (for the doubled ingredients)

Optional: Cake Mixing Machine (Kitchenaid sort of thing), Staff mixer with chopping attachment or processor.

Method

Preheat the oven to 180°C

Grease with a bit butter (use the paper wrapper from the butter if you have a bit handy) a 20cm square baking dish, I found a Pyrex glass one was good for the best results.

Break the bar of chocolate into single chunks and melt in a double boiler or 1- 1 1/2 minutes on medium in a microwave then stir well to melt all the lumps.

In a large bowl, or the mixing bowl from a cake mixer, combine the melted chocolate, wizzed vegetables, sugar, sieved cocoa powder, softenened butter and vanilla and whisk for a couple of minutes into a muddy smooth and creamy goo. Make sure you go for it, yes, a couple of minutes. I used the whisk on the cake mixer machine, started slowly then let it rip for a couple of minutes. 

Whisk in the egg whites. I used a staff mixer to give it a final wizz to really make sure the spinach is as hard to detect by children as possible, it also adds more air to the mix. Sieve the flour, baking powder and salt on top and fold in with a big silicone spatula or wooden spoon.

Turn out into the baking dish and bake for 35 to 40 minutes, to test, use a knife and it should come out clean.

Cool completely before dividing into squares, 12-16 depending on how generous you want them to be. With a 30x 20cm Pyrex dish and cut it long ways by three then by 6 to make 18 rectangles. They went down a treat with Leon's class of 14 and there were a couple over for the teachers and assistants.

For the sandwich cake once it was cooled completely, spread a thin layer of hazelnut chocolate spread in the middle.

Melt the 2nd bar of chocolate (microwave medium for 1 minute, then stir all the lumps left until smooth. Use a spreading spatula to gradually add the chocolate starting in the middle and spread out to the edges then smooth out and leave to cool.