Combine gluten-free flour, cornstarch, sugar, baking soda, and baking powder in a large bowl. Add almond milk, eggs, coconut oil, vanilla extract, and lemon juice; stir until batter is well combined.
Spray a griddle lightly with coconut oil; heat over medium-low heat. Drop batter by large spoonfuls onto the griddle and cook until bubbles form and the edges are dry, 3 to 4 minutes. Flip and cook until browned on the other side, 2 to 3 minutes. Repeat with remaining batter.