1. Prepare the lentils by rinsing in a fine-mesh strainer and remove any debris. Place them in a medium saucepan and cover with water, as per the directions on the packet. Cook until the lentils are tender but not mushy. Drain and set aside.
2. In a large, deep skillet or pot, heat the olive oil over medium heat. Add the chopped onion and cook for 2-3 minutes until it begins to soften. Add the minced garlic and cook for an additional minute.
3. Stir in the chopped carrot, celery, and red bell pepper. Cook for 5-7 minutes, or until the vegetables start to soften.
4. Add the paprika, dried oregano, dried basil, salt, and black pepper. Stir well to coat the vegetables with the seasonings.
5. Pour in the crushed tomatoes and vegetable stock. Add the bay leaf, and stir to combine. Bring the mixture to a gentle simmer.
6. Add the cooked lentils, kidney beans, and butterbeans to the tomato mixture. Stir to combine.
7. Reduce the heat to low, cover the skillet or pot, and let the mixture simmer for about 20-30 minutes. Stir occasionally to make sure it doesn't stick. Top up with a little extra stock if needed.
8. Taste and adjust the seasoning as needed, adding more salt, pepper, or even paprika if you wish.
9. Once the mixed bean ragu has thickened and the vegetables are tender, remove the bay leaf.

Tips:

1. You can swap the legumes for others as you wish.
2. You can use pre-cooked lentils for speed, just skip step 1.
3. You can vary the herbs and spices as desired. Another nice option with this is a little chilli (dried flakes are fine).