I start by roasting the poblano peppers over high heat or under a broiler until skins blacken. After cooling, I peel, seed, and dice them into bite-sized pieces for the mac.
I boil pasta in salted water until al dente, then drain and set aside. A quick tip: slightly undercook, so it doesn’t get mushy when baked.
Melt butter in a skillet, whisk in flour to make a roux, and cook for a minute. Slowly add cream, then mascarpone, and stir in the cheeses and seasonings until smooth.
Mix the cooked pasta and roasted poblanos into the cheese sauce. Transfer to a greased baking dish, sprinkle panko breadcrumbs on top, and bake at 375°F (190°C) until golden and bubbly.