In a large bowl, whisk the mashed bananas, eggs, plant milk, oil, sweetener, and vanilla until smooth.

Add the oat flour, almond flour, baking powder, baking soda, and salt. Fold gently until just combined; avoid overmixing.

Fold in chopped nuts and chocolate chips if using.

Pour the batter into the prepared pan and smooth the top. Bake for 40–45 minutes, until a skewer inserted in the center comes out dry with a few warm crumbs.

Cool in the pan on a wire rack for 15 minutes, then lift out using the parchment and cool completely before slicing.