Make the Orange Muesli Crumble
Preheat your oven to 180°C (350°F) / 160°C fan / gas mark 4 and line a baking tray with greaseproof paper.
In a food processor or a large bowl, combine the flour, brown sugar, chopped butter, oats, and salt. Pulse or rub with your fingertips until the mixture resembles coarse breadcrumbs.
Add the orange juice and mix briefly until just combined. The mixture will be a little sticky; be careful not to over-mix.
Spread the mixture evenly onto your prepared baking tray, breaking up any large clumps.
Bake for 20-25 minutes, turning the mixture with a spatula every 5 minutes to ensure it bakes evenly to a golden brown.
Let the crumble cool completely on the tray.
Once cool, break it into smaller, muesli-sized pieces and stir in the candied orange peel.
Prepare the Chocolate Ganache
Place the chopped milk chocolate in a medium, heatproof bowl.
In a small saucepan, bring the walnut oil and 210g (7.4 oz) of whipping cream to a boil.
Immediately pour the hot cream mixture over the chocolate.
Let it sit for a minute, then stir gently until the chocolate is completely melted and the ganache is smooth and glossy.
Create the Walnut Praline
Lay a 30cm piece of greaseproof paper on your work surface.
Sprinkle the granulated sugar in an even layer in a clean, dry frying pan over a gentle heat.
Allow the sugar to melt and caramelize without stirring. Watch it closely!
Once the sugar turns a beautiful golden caramel colour, add the walnuts and stir quickly to coat them. Be very careful as the caramel is extremely hot.
Immediately turn the caramelized walnuts out onto the greaseproof paper and spread them out.
Let them cool completely for about 10 minutes.
Once cool and hard, break the praline into pieces and place in a bowl. Gently crush them with the end of a rolling pin.
Assemble the Dessert
When you're ready to serve, whip the remaining 100g (3.5 oz) of cream to soft peaks.
Gently fold the crushed walnut praline into the whipped cream.
To serve, place a few spoonfuls of the orange muesli crumble in the bottom of each serving bowl.
Use a warm ice-cream scoop to place a perfect ball of the chocolate ganache on top of the muesli.
Add a generous dollop of the walnut praline cream and finish with a sprinkle of freshly grated orange zest.