Combine oats, milk, bananas, brown sugar, eggs, baking powder, cinnamon, vanilla and salt in a large bowl. Fold in pecans. Divide the mixture among the muffin cups (about 1/3 cup each). Bake until a toothpick inserted in the center comes out clean, about 25 minutes. Cool in the pan for 10 minutes, then turn out onto a wire rack. Serve warm or at room temperature.