Preheat waffle iron.
Drain and rinse the canned beans. In a small pot combine the beans, thyme, and chicken stock. Season with gray salt and pepper and bring to a simmer for about 5 minutes over medium-high heat. Remove from the heat and allow to cool to room temperature. Meanwhile in a large mixing bowl combine the flour, sugar, baking powder, and teaspoon salt.
Add the beans and their cooking liquid to a food processor and pulse to puree. Add the eggs, milk, and olive oil to the bean mixture and puree until smooth. Whisk the wet mixture into the dry slowly to avoid any lumps. Let the batter rest briefly and griddle the waffles according manufacturer's instructions.