Preheat the oven to 180°C (350°F), gas 4.
Put 2 cups of pecans into a food processor and process until they start to clump, and oils start to release.
Transfer the pecan mixture into a large bowl and mix with the rest of the ingredients, except the rice syrup.
In a small saucepan, warm the brown rice syrup to reduce its viscosity. Pour into the mixture and mix well.
Using your hands, squeeze the dough over and over to combine. You should be able to form a ball with it. If it’s too dry, add a little water.
Transfer the pecan dough into a 9-inch push-up fluted flan dish and smooth out evenly. Press down firmly with your fingers, bringing it up along the sides and pressing as firmly as you can.
Prick the dough with a fork to make a cross.
Bake for 10–12 minutes until slightly golden. Remove from the oven and allow to cool on a wire rack.