Preheat your oven to 350°F and line a baking sheet with parchment paper.

In a small bowl, mash the blueberries with a fork until they form a rough puree with small berry pieces.

Add 1/2 cup of the oat flour to the mashed blueberries and stir until a thick, slightly sticky purple dough forms. If it seems too wet, add a little more flour until it holds together.

In a separate bowl, combine the peanut butter and unsweetened applesauce and mix until smooth.

Add the remaining 1/2 cup oat flour and the ground flaxseed (if using) to the peanut butter mixture and stir until a soft, non-sticky dough forms, adding 1–2 tbsp water only if the dough is dry and crumbly.

Lightly flour your work surface with a small amount of oat flour. Divide each dough into 12 equal small logs.

Take one blueberry log and one peanut butter log, gently roll each into a rope about 5–6 inches long, then place them side by side and twist them together to form a spiral stick. Pinch the ends to seal. Repeat with remaining dough pieces.

Arrange the twisted sticks on the prepared baking sheet, spacing them slightly apart.

Bake for 18–20 minutes, or until the twists are firm and lightly golden at the edges.

Remove from the oven and let the twists cool completely on a wire rack before serving to your dog.