Preheat the oven to 350° F (175° C). Grease an 8x8 inch baking dish with vegan butter or coconut oil.
Put the chia seeds and warm water in a cup. Set aside.
In a large bowl combine the oats, brown sugar, baking powder, cinnamon and sea salt. Stir to combine.
In a small bowl combine the milk, melted coconut oil, vanilla and the chia/water mixture.
Pour the wet ingredients into the bowl with the dry ingredients. Stir in the chopped peaches.
Pour the mixture into the prepared pan, and topped with the sliced peaches. Sprinkle with the slivered almonds. Bake for 45 minutes.
Allow the baked oatmeal to rest in the pan for 5-10 minutes before cutting it into squares and serving.