¾ cup/70g blanched whole hazelnuts
Cooking oil spray
6 Tbsp/85 g unsalted butter, cubed
2 Tbsp extra-virgin olive oil
1 tsp hazelnut extract
1 ¼ cup/250 g superfine/caster sugar
¾ cup/60g unsweetened cocoa
¼ tsp fine sea salt
2 cold large eggs
½ cup/70 g all-purpose flour
2 to 4 Tbsp/30 to 60ml cold water
- Preheat the oven to 325F/165C.
- Spray an 8 in/20 cm square baking pan with a bit of cooking oil and line with parchment paper. Spray the parchment paper with the cooking oil.
- Heat a medium stainless-steel skillet over medium-high heat, add the hazelnuts, and toast until they turn lightly golden brown and fragrant, 3 to 4 minutes. Swirl the pan occasionally to prevent the nuts from scorching. Transfer the nuts to a mortar and pestle, and gently crush them. If you prefer, chop them with a knife. Keep aside.
- Melt the butter in a small stainless-steel saucepan over medium heat and cook until the milk solids separate and start to turn reddish-brown. The time will vary, so I’m not going to tell you how long it will take; color is a better indicator for this step. Once the milk solids change color, remove the saucepan from the heat and whisk to remove any solids stuck to the bottom. Transfer the browned butter with the milk solids to a medium mixing bowl.
- Add and whisk in the olive oil, hazelnut extract, sugar, cocoa, and salt by hand until combined. Whisk in one egg at a time, about 30 seconds. Add the flour and 2 Tbsp of water, and whisk to combine. If it is a little stiff, add the remaining 2 Tbsp of water. Whisk until there are no visible dry flecks of flour. Fold in the crushed toasted hazelnuts with a silicone spatula. Transfer to the prepared baking pan and level with an offset spatula. Bake in the preheated oven for 20 to 25 minutes, until the top, develops a crust and begins to crack, and a skewer, when inserted through the center, comes out slightly moist with the batter.
- Let the brownie cool in the pan for 5 minutes. Remove the brownie using the sides of the parchment paper, and transfer to a cutting board, cut into 16 squares. Store cooled brownies in an airtight container in the refrigerator for up to 3 days.
- For the cooking oil spray, use a neutral oil like grapeseed or extra-virgin olive oil.
- There are many options for hazelnut extract; this one from LorAnn is what I use.
- Use superfine, aka caster sugar, for the brownies because the smaller crystal size will produce a moister brownie. The smaller the crystal size, the better the sugar absorbs moisture (no one wants a dry brownie).
- Like most baked desserts, this one depends on ratios. The butter is browned and loses water; some of it needs to be added back, so I add some towards the end.