Boil the potatoes: Bring a large pot of salted water to a boil. Add the baby potatoes and cook for about 15 minutes until fork-tender. Drain and let them cool slightly.
Smash and bake: Preheat the oven to 425°F (218°C). Place the boiled potatoes on a parchment-lined baking sheet and gently smash them with a potato masher or the back of a spoon. Drizzle with olive oil, season with salt and pepper, and bake for 20 minutes until crispy.
Add the cheese: Sprinkle shredded cheddar over the crispy potatoes and return to the oven for 5 minutes until melted and bubbly. Garnish with fresh chives.
Sear the steak bites: While the potatoes bake, heat a large skillet over medium-high heat. Melt 2 tablespoons of butter, season the steak cubes with salt and pepper, and sear them in a single layer for 2-3 minutes per side until browned. Remove from the pan and set aside.
Make the garlic butter sauce: In the same skillet, melt the remaining butter and sauté the minced garlic for 30 seconds until fragrant. Return the steak bites to the pan and toss to coat in the garlic butter.
Serve and garnish: Plate the steak bites with the cheesy smashed potatoes. Garnish with fresh parsley.