In a small bowl whisk together all of the ingredients minus the beans, onion and arrowroot powder.
Heat a medium sized saucepan or pot over medium heat. Spray the bottom with cooking oil then add in the diced onion. Sauté 2-3 minutes then add in the beans and the sauce. Stir together until combined and bring to a simmer.
In the same bowl that the sauce was in whisk together the arrowroot powder or cornstarch with a teaspoon of water until it's smooth. Pour it into the bean mixture and stir together until combined.
Cover the pan with a lid and simmer over low heat for another 5-7 minutes or until the sauce has thickened and the beans are heated through.
Taste for seasoning then serve on whole wheat or gluten-free slider rolls topped with dill pickle chips, lettuce and tomato.
The sloppy Joe mixture can be made 1-2 days in advance if needed and reheated on the stove or in the microwave. Just like with chili, they taste even better the next day.