Line an 8 by 8 inch baking dish or silicone mold with parchment paper, leaving some overhang for easy lifting.

Add the rolled oats and puffed rice cereal to a large mixing bowl and stir until evenly combined.

Place the coconut oil in a small saucepan over low heat and warm just until fully melted.

Add the peanut butter, honey, and water to the melted coconut oil and stir constantly over low heat until the mixture is smooth and glossy.

Remove the saucepan from the heat and immediately pour the warm mixture over the oats and rice cereal.

Stir with a sturdy spoon or spatula until all of the dry ingredients are evenly coated and the mixture looks sticky and cohesive; if it seems too dry, stir in an extra teaspoon or two of water.

Transfer the mixture to the prepared dish and press it firmly into an even layer with clean hands or the back of a spatula; for bite size treats, scoop and roll small portions into balls instead and place them on a parchment lined tray.

Refrigerate the pan or tray for 30 minutes, until the treats feel firm to the touch.

Lift the chilled slab from the pan using the parchment overhang and set it on a cutting board, then cut into 7 equal bars or into smaller pieces sized appropriately for your dog.

Serve your dog a small portion as a special treat and store remaining pieces in an airtight container in the refrigerator.