Season chicken legs with salt
Heat cooking oil in a cast iron skillet over medium-low heat
Place chicken legs skin-side down and use a chef press to get a good crust, cooking for about 8 minutes
Flip chicken and cook until golden
Transfer to a 400 degree oven and bake for 15-20 minutes until cooked through
While chicken cooks, whisk together tomato paste, Dijon mustard, and white wine or rosé in a saucepan
Add a pinch of salt and reduce the sauce for 10-12 minutes until wine is cooked out and sauce thickens
Stir in heavy cream and cold butter
Bring sauce to a boil and let it thicken until it coats the back of a spoon
Let chicken rest, then serve with sauce alongside, preserving the crispy skin
