Preheat oven to 350ºF and line a standard loaf pan with parchment paper.
Mix all streusel topping ingredients in a small bowl until crumbly. Set aside.
Combine dry ingredients in a medium-sized bowl. Set aside.
In a large bowl, cream together brown sugar, oil, and vanilla. Add peanut butter, grated apples, and banana. Mix well. Add eggs and gently mix, then add almond milk until combined.
Slowly add dry ingredients to wet ingredients and mix until smooth.
Transfer batter to loaf pan and top with streusel.
Bake for 50-60 minutes or until a toothpick comes out clean. Let it cool in the pan for a few minutes, then transfer to a cooling rack.