Season drumsticks. Heat 2 tablespoons of oil and butter in a large frying pan over medium heat. Cook chicken, turning, for 10 minutes or until browned.
Meanwhile, place fennel, potatoes and onion on a large oven tray. Drizzle with remaining oil. Season and toss to coat. Squeeze lemon wedges and add to tray. Nestle chicken amongst vegetables.
Add Massel Liquid Stock Chicken Style to frying pan and scrape base to dislodge any brown bits. Pour over vegetables. Bake for 1 hour, basting chicken and vegetables halfway through.
Increase oven to 220 C or 200 C fan forced. Add tomatoes and bake for 15 minutes.