Preheat the oven to 350°F and line a baking sheet with parchment paper or a silicone baking mat.

In a medium bowl, mash the banana until mostly smooth.

Add the peanut butter and water to the banana and whisk or stir until the mixture is creamy and well combined.

Sprinkle in the whole wheat flour gradually, stirring until a soft dough starts to form.

Switch to your hands and gently knead the dough in the bowl until it is smooth and slightly tacky but not sticky. If it is too sticky, knead in a small amount of extra flour.

Lightly flour a clean work surface and roll the dough into a rectangle about 0.25 inch thick.

Using a sharp knife or pizza cutter, slice the dough into long strips about 0.5 inch wide.

Take 2 strips and twist them together from end to end to form a spiral, then place the twist on the prepared baking sheet. Repeat with the remaining strips, leaving a little space between each twist.

Bake for 18 to 20 minutes, or until the edges are light golden and the centers feel set.

Transfer the treats to a wire rack and let them cool completely until crisp before serving to your dog.