Preheat the oven to 190°C and line a 9-inch cake tin with baking paper
Add all peach ingredients except Grand Marnier to the tin and toss together
Place in the preheated oven for 20 minutes
Turn to grill setting at 220°C fan, add Grand Marnier, and grill for 4 minutes to caramelize
Turn half of the peaches over
Reduce heat to 170°C
In a bowl, whisk together olive oil, caster sugar, honey, and eggs with yolks
Stir in ground almonds, flour, baking powder, bicarbonate of soda, and sea salt
Mix in crème fraîche, vanilla extract, and cinnamon powder
Pour the cake batter over the roasted peaches
Bake for 45 minutes in the middle of the oven until a skewer inserted comes out fairly clean
Serve with crème fraîche, either straightaway or after cooling for enhanced flavor
