Preheat the oven to 350 degrees F and lightly grease a 9x13 baking pan or dish.
In a small bowl, beat together the flaxseed meal and water for 1 minute. Place in the refrigerator for 10 minutes.
Using a fork or potato masher, mash the bananas and stir in the peanut butter, oil, plant milk, vanilla, flour, sugar, baking powder, salt, and flaxseed mixture until it’s well-combined.
Pour the batter into the prepared baking pan, use the fruit preserves to create a layer of swirls on top of the batter, and bake for 50 minutes. Test by sticking a toothpick in the middle of the loaf. If the toothpick comes out dry, the loaf is done. If it’s not, bake in 5-minute increments until the toothpick comes out dry.