With the rack in the middle position, preheat the oven to 180 °C (350 °F). Butter a 20-cm (8-inch) springform pan. Line the bottom with parchment paper.
In the food processor, process half the oatmeal into a fine powder. Transfer to a bowl and add the remaining oatmeal, the flour, and baking powder. Stir to combine. Set aside.
In another bowl, beat the eggs, sugar, and vanilla with an electric mixer until the mixture triples in volume. At low speed, drizzle in the oil. Stir in the dry ingredients alternately with the milk. Add the chocolate chips, except for 15 ml (1 tablespoon) and stir with a wooden spoon.
Pour into the prepared pan and sprinkle with the remaining chocolate chips. Bake for about 1 hour or until a toothpick inserted in the centre of the cake comes out clean. Let cool and unmould. Let cool on a wire rack.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.