Preheat the oven to 375 degrees F. Grease the silicone molds or mini muffin tin.
Place the oats, chia seeds, cinnamon, vanilla, raisins, and maple syrup or honey, if using, into a medium bowl.
Add the warm milk and stir. Let sit for 5 minutes.
Press about 1 tablespoon batter into each mold or mini muffin cup. Bake for 10-14 minutes, or until the oatmeal is set and golden brown around the edges.
Remove from oven and let cool in pan for 5-10 minutes, then on a wire rack. Serve slightly warm or chilled.