In a bowl, mix goat's cheese, cream and herbs and season to taste. Wipe chicken with paper towel, cut down one side of each fillet to form a pocket and fill with goat's cheese mixture.
Heat oil in a heavy-based frying pan on high. Cook chicken for 4-5 minutes each side, until cooked through and golden brown. Remove to a plate, cover loosely with foil and set aside.
Add 10g of butter to pan on high heat. Add stock and wine, bring to boil and reduce by half. Reduce heat to medium and whisk in remaining butter, a piece at a time, until smooth and foamy. Return chicken to pan and cook for 1 minute, until heated through. Season to taste and serve with deep-fried sage leaves, if you like.