Heat a layer of olive oil in your skillet. Add the onions and cook over a medium heat for about 10-15 minutes. We want them reduced and soft, but starting to crisp up a little at the edges.
olive oil, 1 red onion
Add the garlic to the pan and cook until soft.
3 cloves garlic
Add the fennel seeds and cook for about 30 seconds, until the fragrance is released and then add the smoked paprika and dried sage. Mix through to coat the onions.
1/4 tsp fennel seeds, 1/4 tsp smoked paprika, 1/2 tsp dried sage
Add the cherry tomatoes to the pan and continue to cook for a few moments until they start to break down and release their liquid.
8 oz cherry or grape tomatoes
Add the white wine and stir through. It will bubble up and help un-stick anything that's getting stuck on the bottom of the pan before being absorbed by the tomatoes.
1/4 cup white wine
Add the beans to the pan along with a little bit of the cooking water, just enough to keep the skillet moist. Simmer for about 5 minutes, allowing the beans to absorb the flavor. Use a wooden spoon or potato masher to break down and mash some of the beans if you'd prefer a more creamy finish. Add salt and pepper to taste - especially important if you're using canned beans. Once the beans have cooked down to the texture you like, remove from the heat and stir the feta through.
1.5 cups cooked navy beans, 3.5 oz feta cheese
If you are using the fried sage garnish, prepare that now. In a small saucepan or frying pan, heat a little butter or olive oil and fry the sage briefly until crisp (about 30 seconds should do it). Remove from the heat immediately and pour into a bowl.
10 fresh sage leaves
Top the beans with fried sage and serve.