Peanut Butter and Banana Dog Treats
Adapted slightly from

1 egg
1/2 cup peanut butter
1 mashed banana
1 cup whole wheat flour
1/2 cup rolled oats
1 egg white, lightly beaten, for brushing (optional)

I skipped brushing the tops with egg white. It will look shiny and nicer if you do.

Preheat oven to 300 degrees F (150 degrees C). Line a baking sheet with parchment paper.
Stir together the egg, peanut butter, banana in a medium bowl; blend thoroughly. Stir in the flour and rolled oats; mix well. Turn dough out onto a floured surface and roll to 1/4 inch thick. Cut into desired shapes with a cookie cutter, place on prepared baking sheet, and brush tops with egg white.
Bake treats until dried and golden brown, about 30 minutes, depending on size. Remove from oven and cool on a wire rack.