In a large pot, boil potatoes until tender. Drain and set aside.

In a separate pot, melt butter over medium heat. Whisk in flour and cook for 1-2 minutes, stirring constantly.

Gradually whisk in milk until smooth. Bring to a simmer and cook until thickened, about 3-4 minutes.

Add cooked potatoes back to the pot. Mash or blend to desired consistency.

Stir in heavy cream and cook until heated through.

Remove from heat and stir in cheddar cheese until melted and smooth.

Season with salt and pepper to taste.

In a skillet, heat olive oil over medium-high heat. Sear steak until desired doneness. Let rest, then slice or cube.

Add steak to the soup and stir to combine.

Serve hot, garnished with sliced green onions.