Prepare pasta in salted water according to pkg. directions while preparing the sauce; keep warm. Heat milk in a small saucepan, but do not boil; keep warm. Melt butter in an extra-large oven-safe sauté pan; add onion to the butter and cook over medium heat until onion is translucent and soft (about 5 min.). Sprinkle flour over butter and onion in the sauté pan; whisk until smooth. Cook flour mixture over medium-low heat for 2 min., whisking constantly. While continuing to whisk, add warm milk, then gochujang; cook and whisk until thick and smooth (about 5 min.). Remove pan from the heat; whisk in cheese until smooth. Season with salt and pepper to taste. Stir kimchi, mushrooms and hot, drained pasta into the sauce. Serve immediately.
SAUTÉED SHIITAKE MUSHROOMS: In an extra-large skillet over medium-high heat, heat enough oil to lightly coat pan. Add 5 oz. sliced mushrooms; cook, stirring frequently, until tender and dark on the edges. Remove from heat; season to taste with salt and pepper.
Good to Know: Find Boar's Head Products in the Deli Department.