Sauté the finely chopped onion in a large pot or Dutch oven with the olive oil over medium heat. As the onion turns translucent and begins to brown slightly, add in the minced garlic, diced celery, and chopped carrots. Continue to sauté for about 10 minutes until all the veggies soften and develop a rich color.
Pour in the white grape juice and allow it to cook down until most of the liquid has evaporated—this should take around 5 minutes.
Once deglazed, add all remaining ingredients except for the kale into the pot; this includes rinsed cannellini beans, broth (starting with 2 1/2 cups), tomato paste, salt, pepper, red pepper flakes, Italian seasoning, bay leaves, thyme, and oregano. Stir well to combine everything evenly before bringing it all to a boil.
After reaching a boil, cover your pot and reduce the heat to low; let it simmer gently for about 15 minutes.