Pre-heat oven to 325F/160C/gas mark 3. Put top shelf in the middle of the oven.

Spray a 9" (22-24cm) round cake pan with non-stick spray and line with parchment paper cut to fit the bottom.

Put chia seeds in a small bowl with 4 tablespoons (60ml) filtered water. Set aside.

After sifting and measuring the flour and baking powder, whisk in cornmeal and salt in a medium-sized bowl. Set aside.

Wash and dry oranges.

Cut your orange slices and set aside: Using a sharp, serrated knife, cut a very thin slice from the center of the largest orange. That will be the center of your design. Slice the other oranges to create enough thin slices to fill the bottom of the pan. I cut some in half and some in quarters to create the pattern. The most important thing is for all slices to be the same thickness.

Juice at least one orange to make 1/2 cup (125ml) of orange juice. Add about half an orange cut into chunks (minus seeds or hard ends) to the food processor.

Put the margarine and 2 tablespoons (30ml) of maple syrup in a small saucepan and bring just to a boil, stirring well.

Pour it into the prepared baking pan, tilting to cover the bottom evenly. Create your orange slice design in the bottom, fitting pieces as closely together as possible.

Add orange chunks to food processor fitted with an S-blade and pulse until finely chopped. Add hazelnuts, 1/2 cup (125ml) maple syrup, prepared orange juice, olive oil, chia seed mixture, and the leaves from 3 sprigs of thyme. Pulse until well mixed.

Add flour mixture and pulse a few times to combine.

Pour batter on top of orange slices in the cake pan, smoothing the top. Bake 45-50 minutes until evenly golden, firm when pressed in the center, and a toothpick will come out with just a few crumbs attached, no goo.

Cool on a wire rack for 15 minutes. Run a knife or thin spatula around the edge to release.

Place your serving plate face down on top of the pan, then flip the whole thing over and wait for that satisfying thunk as it drops onto the plate. Remove pan, peel off parchment paper.

Top with a sprinkle of fresh thyme leaves and orange zest right before serving.