Boil Potatoes: Place the whole, well-cleaned potatoes in a pot with cold water and let them boil. Start with cold water to ensure they cook evenly. Add two sprigs of rosemary, two cloves of garlic, and salt.

Prepare Chicken Thighs: Take the chicken thighs and cut around the tendons. Make a cut down to the bone to have a flat surface. Repeat this process with all the thighs.

Sear Chicken: In a hot skillet, add a little olive oil and place the chicken thighs skin-side down. Once browned, remove them from the skillet and place them in a baking dish.

Make the Sauce: In the same skillet, pour in about 150ml of the water from boiling the potatoes, add the mustard, lower the heat, and add the tarragon, lemon zest, a little olive oil, and the cherry tomatoes.

Combine and Bake: Pour the sauce over the chicken in the baking dish, ensuring it doesn’t touch the skin to keep it crispy. Bake under the grill for 20 minutes until cooked through.

Fry Potatoes: In a pot, heat 1.5 liters of olive oil over high heat. Once the potatoes are done, remove them from the water and break them into large pieces with a fork. Place the potatoes into the hot olive oil and fry until golden brown.

Drain and Serve: Once cooked, place the potatoes on absorbent paper to remove excess oil. Serve alongside the chicken.