1) In a large nonstick saute pan over medium heat, add 2 tablespoons of olive oil. Add pancetta and stir with a wooden spoon so you have some nice curls. Cook for 4 to 5 minutes until crispy then remove to paper towels. Reserve pancetta fat in the pan and add the chicken stock, lemon, garlic, thyme and bay leaf. Bring to the boil then and then add escarole and clams. Cover and simmer for 15 minutes until clams open. Season with salt, pepper, and sugar.
2) Season bass fillets with salt and pepper. Place a large saute pan over medium heat and add remaining 2 tablespoons olive oil. Once oil is smoking add the fillets, skin side down and don't move for 3 minutes. Using a fish spatula carefully pick up fillets and set in the pan over escarole and poaching flesh side down for 30 seconds.
3) Divide escarole and clams with the broth on individual plates, top each with a bass fillet and garnish with the crispy pancetta.