Fries: Preheat the oven to 190º C fan. Line a large baking tray. Rinse 2 potatoes and slice into shoestring fries. Add to lined tray and spray with oil and season with 1 tsp salt & pepper. Place in the oven and cook for 35-40 minutes, stirring halfway.
Make tomato salad: Halve the cherry tomatoes and thinly slice 7 basil leaves. Add to a bowl and top with 3 tsp olive oil and 1 tsp salt & pepper. Mix well and set aside.
Cook sauce: Slice 200g mushrooms into small pieces. Preheat a small pot to medium heat and add 10g butter. Once melted, add chopped mushrooms and cook for 2-3 minutes, until softened. Add 1 tsp salt & pepper and 1/2 tsp mustard. Mix well and continue stirring, and reduce the heat to low.
Steak: Heat a large pan to a high heat and add 3 tsp neutral oil. Meanwhile, season steaks with 1 tsp salt & pepper. Once the pan is hot, cook steaks for 2-3 minutes per side, or until cooked to desired level. Remove from pan and rest. Once the steak is resting, add 3/4 cup cream to mushroom sauce, increase the heat and bring to a boil. Taste and adjust seasoning if required.
Assemble: Add sliced steak to half of the plate, add fries to the other half, and top with mushroom sauce. Serve with tomato salad on the side.