Remove the chicken from the fridge and let it come to room temp before cooking. When you're ready to start, place the chicken breasts in a bowl with 2 tbsp olive oil and a little salt and pepper.
While the chicken comes to temp, peel the shallots and slice into half moons. Peel and finely slice the garlic. Crumble the stock cube into a heatproof jug and stir in 150ml boiling water to dissolve it.
Heat a shallow casserole pan over a medium-high heat. Once hot, add any oil from the bowl and the chicken breasts, skin-side down. Cook for 3-5 mins without disturbing them, so they're golden, then turn and cook for a further 2 mins to colour the underside. Remove the chicken from the pan and set aside on a plate.
Lower the heat and add the shallots with a pinch of salt. Cover and cook for 10 mins till the shallots are soft but without colour. Add the garlic and cook for 5 mins. Add the thyme sprigs, chicken stock, half the jar of honey, 1 tsp vinegar and the chicken (skin-side up). Cover. Cook for 10 mins.
While the chicken cooks, pour 525ml boiling water into a pan. Add a pinch of salt. Bring back to the boil, then lower the heat and add the polenta in a steady stream, stirring constantly. Continue to stir till the polenta is thick and smooth. Stir through the butter. Set aside.
Slice the figs in half. Slice off any thick stalks from the spinach, keeping the leaves intact. Add the figs, cut-side up, to the pan. Baste the figs so they're glossy. Cook for a further 5 mins till the chicken is cooked through.
Add the spinach to the chicken and wilt it for 1 min, folding it through the braise.
Spoon the hot polenta into shallow bowls and top with chicken, figs and juices from the pan.