I start by combining flour, cocoa, and sugar in a bowl. Then, I cut in cold butter until the mixture looks like coarse crumbs. Adding the egg yolk and a touch of water brings the dough together without overworking it.
I press the dough evenly into the tart pan, prick the bottom with a fork, and bake at 350°F (175°C) for about 12-15 minutes. This ensures a crisp shell that won’t get soggy when the ganache is added.
I gently heat cream in a small saucepan until just simmering, then pour it over chopped chocolate. I stir until smooth and glossy, then fold in butter and vanilla. Pouring this into the cooled tart shell is always the most satisfying part.
I place the tart in the fridge for 2-3 hours, allowing the ganache to set completely. This step is crucial for a firm, sliceable tart.
Before serving, I spread a thin layer of raspberry jam on top and arrange fresh raspberries decoratively. It adds brightness, flavor, and a beautiful visual contrast with the dark chocolate.