Wash and peel the potatoes and cut them into thick sticks. Spread on a baking tray lined with baking paper. Sprinkle with 1 tsp. salt and paprika. Spray or sprinkle with 1 tbsp. oil and mix once on the baking tray. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 30 minutes.
Pour milk with mustard and lemon juice into a tall mixing bowl. Mix with a hand blender, slowly adding 100 ml oil in a thin stream until a white-creamy mayonnaise is obtained. Season to taste with salt and pepper. Serve with the chips.