Step 1 Bring a small saucepan of water to the boil. Add potato and cook for 5 minutes, or until just tender, then drain and set aside.
Step 2 Reduce heat to low. Add baby carrots, rosemary and honey to saucepan with 1/2 cup water; cover and cook for 5 minutes, or until carrots are just tender. Uncover pan, increase heat to medium– high and cook for 5 minutes, or until liquid evaporates and carrots are coated in honey. Cover pan to keep warm and set aside.
Step 3 Meanwhile, heat half the olive oil in a large non-stick frying pan over medium–high heat. Add reserved cooked potato and stir occasionally for 10–12 minutes, or until crisp and golden.
Step 4 Push potato to one side of pan. Sprinkle chilli flakes and fennel seeds onto steak, add to pan and cook for 3 minutes per side, or until done to your liking. Transfer steak and potato to a plate; cover.
Step 5 Heat remaining olive oil in same frying pan. Add baby spinach and cook until just wilted; transfer to a serving plate with steak, potato and carrots. Serve steak with a dollop of mustard (if using).