Pre-heat oven to 350F (180C). Grease a 9x2 inch round cake pan. Line with parchment paper and grease it as well.
In a medium bowl, combine the turbinado sugar and cornstarch. Add the cranberries and toss to coat. Arrange the cranberries in a single layer on the bottom of the cake pan.
Whisk flour, sugar, baking powder in a large bowl. Add canola oil, lemon zest, apple pure, oat milk, and mix it well with a wooden spoon or spatula until you get a smooth batter, about one or two minutes. Do not overmix.
Pour the batter into the prepared pan with cranberries. Bake it for 40 minutes or until the edges begin to pull away from the pan or a toothpick inserted in the center of the cake comes out clean. Let it cool for 30 minutes before turning it out. Run a knife around the pan to detach the cake, turn the cake into the serving plate and peel the parchment paper.