A dream for chocolate hazelnut lovers! Ground up hazelnuts and oreo crumbs make up the crust, the filling is a smooth milk chocolate ganache studded with bits of chopped hazelnut. The tart is topped with a super creamy hazelnut mousse made with cream cheese and homemade hazelnut paste.
The hazelnut and milk chocolate pairing is always expectedly wonderful, but this tart allows you to experience it in a variety of textures: crunch in the oreo and nutty crust, a softer ferrero rocher like ganache center, and the top – smooth hazelnut bliss, made even more flavorful with the tang of cream cheese. It’s not a lot of work (there’s more chilling and resting than anything) and once done you have quite a fancy, pâtisserie level dish.
I prefer blanched for this, since we’ll be making hazelnut butter for the mousse but if you don’t mind some flecks of darker brown in your mousse it won’t make too much of a difference.
You will want to toast them yourself, this brings out the flavor so you’ll have freshly toasted very flavorful and crunchy nuts.
For the ganache I prefer a mix of milk and dark chocolates. Since milk chocolates tend to vary in how much milk and sugar is added it can make it a little difficult to know exactly how much heavy cream to get the right ganache consistency.
Milk chocolates that are low in cocoa solids (like the ‘extra creamy’ varieties) will need less heavy cream or they’ll be overly loose and soft. If you’re able, get a milk chocolate that tells you the percentage of cocoa solids. For the recipe below I’d say use something that’s around 45-50% cocoa solids.
If you wish to make this layer quite sweet and predominantly milk chocolate I’d reduce the amount of heavy cream added to be 50% of the total of chocolate (so if you use 350g milk chocolate, use 175g of heavy cream).
If you have a higher tolerance for darker and don’t mind the loss of sweetness, you might appreciate using all dark chocolate, in this case I’d match the heavy cream to the weight of chocolate: 350g each (you’ll have a thicker layer of ganache in this case so you could reduce both the chocolate and heavy cream 250g each to avoid that).
Chocolate Sandwich Cookies
Aka oreos, we’re using a sandwich cookie because the included filling is balanced against how much butter we’re adding. So if you want to use a cookie that doesn’t have a sandwich filling, you’ll need to add more butter to get the ‘wet sand that clumps together’ consistency.
A full fat cream cheese gives better consistency because so it’s quite firm(low fat cream cheeses have more water).
Or heavy whipping cream (they are interchangeable). If you aimed to make this a dairy free tart with dairy free chocolate and df cream cheese you can swap the heavy cream for coconut cream. It should be cold when adding it to the mouse so it can whip up thick, so stick the can in the fridge a few hours before beginning.
Hazelnuts toasted then processed until they release their oils and turn into a liquid paste – like peanut butter.
We’re going to make our own hazelnut butter for the mousse and all we need is a cookie sheet to toast the nuts for about 10 minutes at 350 F, and a food processor to process the nuts.
It can take up to 10 minutes to coax all of the nuts to turn into ‘butter’ or a thin, soupy texture. Scrape down the food processor and press the nuts into the bottom near the blades every now and then to keep it working.
At some point it will turn into a thick glob that’s part paste part bits of nuts, keep processing on high and scraping and pressing down as needed. Stop when it’s running off the spoon.
You can store it in the fridge, it’ll keep for a few weeks.
Once the ganache is in the shell the tart will keep for quite awhile in the fridge (or even freezer in an airtight container).
The mousse however can tend to separate or seep if left too long so it’s best to make that part the day of serving.
Chop chocolate finely: Dark chocolate especially takes time to melt (it has less milk or cream in it) so to avoid the heavy cream cooling before it can fully melt the chocolate, chop it very finely (no bigger than a black bean). The milk chocolate can be in slightly bigger bits as it will melt quicker.
Heat heavy cream: It should be bubbling on the sides and steaming slightly in the center. If you don’t heat it enough it will cool before it can fully melt the chocolate. If you overheat it (like it’s boiling or steaming quite a bit) it will burn the chocolate.
Let sit, stir well: Once you’ve poured the cream over the chocolate give it a quick stir then let it be for a minute. This will encourage the chocolate to begin melting. Then stir, stir, stir to complete the melting, until you have a smooth, shiny ganache.
Fixing a broken ganache: Ganache is broken when the chocolate has melted fully but it looks greasy and separated. If it isn’t too far gone you can sometimes ‘rescue’ it by adding more heavy cream and stirring it in to bring it back together.
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