Here in Italy polpo is a very common ingredient. I tend to buy them fresh and put them immediately in the freezer. A frozen polpo is more quickly tender by boiling. Put the frozen polpo( 700grams for 2p) in a large pan. Add 150 ml of white wine, 2 bay leaves, 2 stems of celery, 2 garlic cloves and 1 chili. Add water until the polpo is almost covered. Heat the pan. Allow to simmer for 1-1,5 h until tender. Cool down and drain. Throw away the boiling liquid.
Slice 2 fennel bulbs. Put them in an oven dish. Spread some olive oil. Bake in the oven at 180° for 30 mins. Stir. Add 2 tomatoes cut in quarters, 4 sliced garlic cloves, 2 chopped chili, some rosemary stems, the polpo cut in pieces and 1 table spoon of fennel seeds and some salt. Bake in the oven for another 30 mins.