Heat a large skillet or cast iron pan over medium-high heat. Add 1 tablespoon butter and 2 tablespoons olive oil. Once the butter melts and the oil shimmers, add baby potatoes cut-side down in a single layer. Season with salt, pepper, dried rosemary, and dried thyme. Cook undisturbed for 3 to 4 minutes to build a golden crust, then stir occasionally for 10 to 12 minutes total until fork-tender and browned all over. Transfer to a plate and set aside.

Keep the heat at medium-high and add 1 tablespoon butter to the same skillet. Arrange steak bites in a single layer without overcrowding, working in batches if needed. Season generously with salt and pepper. Sear for 2 to 3 minutes per side until a deep brown crust forms. Use an instant-read thermometer and pull at 135 degrees F for medium-rare. Do not move the pieces while searing. Remove steak and set aside.

Lower the heat to medium-low. Add the remaining tablespoon of butter and the minced garlic to the skillet. Stir constantly for about 1 minute until lightly golden and fragrant. Watch closely as garlic burns quickly and will turn bitter if overdone.

Return the steak bites and crispy potatoes to the skillet. Toss gently to coat everything in the garlic butter for about 30 seconds. Turn off the heat, scatter fresh parsley on top, and serve immediately.