Chocolate hazelnut brownies with the Thermomix

The result you want is exactly this: a moist, dense center, a thin crackly crust on top, and the crunchy contrast of whole hazelnuts left in big pieces on purpose.

The trick for the crackly top is not whipping the eggs and sugar too much: 45 seconds in the Thermomix is enough, just long enough to combine them without beating in air.

If you want to serve them as a real dessert, a square that's still slightly warm with a scoop of dark chocolate ice cream on top is the combination I make when I have guests.

Fudgy or cakey: it's all about the oven time

Brownies split into two camps, and almost all the difference comes down to baking time, not the ingredients.

• Fudgy (the ones in the photo): a moist, dense center, almost like a chocolate truffle. You get there by pulling them out when the skewer comes out with moist crumbs clinging to it.
• Cakey: drier and more cake-like. That's what you get by leaving them 5-10 minutes longer.

The classic mistake is baking them until they "look done": by then they've already gone too far. A brownie keeps cooking from residual heat even out of the oven, so it should come out when it still looks slightly underdone.

The secret to the crackly crust

That thin, glossy surface that crackles is the signature of a well-made brownie, and it's not random: it forms when the sugar dissolves completely into the eggs and migrates to the surface during baking.

That's why the 45 seconds at speed 4 matter in both directions: enough to dissolve the sugar, not so much that you beat in air. If you overwhip, the brownie puffs up in the oven and then collapses, and the crust never forms.

The other requirement is that the chocolate and butter mixture be just warm, not hot: hot, it would cook the eggs on contact.

Whole hazelnuts, not chopped

It's a deliberate choice: chopped, they'd disappear into the batter giving only a vague flavor; whole, they give the contrast of textures that makes every bite different. For the same reason, fold them in by hand or on reverse at very low speed, since the blades would break them.

If you buy them already toasted and skinned, you save time. Otherwise, 8-10 minutes at 160°C in the oven, then rub them in a kitchen towel to remove the skins: they develop much more flavor, the same trick I use for walnut ice cream.

Why you should wait for it to cool before cutting

Warm, the brownie is still fluid in the middle and the knife drags it: you end up with ragged squares. As it cools, the butter firms up and the structure sets.

For clean, bakery-style cuts: a smooth blade, wiped clean between cuts, and a brownie that's properly cold.

Variations

• Pecans or almonds instead of hazelnuts.
• White chocolate chips: the color contrast when you cut into it looks great.
• Salted caramel: a pinch of flaky salt on top before baking.
• More intense: 70-75% dark chocolate, adding 20 g more sugar.
• Gluten-free: swap the flour for rice or almond flour without changing the method.

Storage

They get better the next day: the center settles and turns even more fudgy. They keep 4-5 days at room temperature in a closed container (never in the fridge, which hardens them), and they freeze very well already cut into squares.