Heat oil, saute onion until soften, then stir in fennel, cook until fragrant
Stir in sliced cabbage, cover and cook on high for 8-10 minutes (until soften), stirring occasionally
Stir in 1 tsp of the additional fennels
Pour crushed tomatoes and broth, cover, cook for 10 minutes (to boil)
Lower heat to medium, uncover stir in the rest of the fennels, bouillon cubes. Cover back and cook for 6 minutes. Meanwhile prepare roux, if lazy like me, just dissolve 2 tbsp flour in enough water
Uncover pot, pour in ‘roux’, stir quickly (it will thicken the stew/soup, a little), season and let cook for 2-3 minutes.