Combine the cubed steak and marinade ingredients, tossing the steak to throughly coat, into an airtight container to sit while you prep the potatoes. Set aside.
Slice each baby potato into quarters (or more depending on size) and place them into a large mixing bowl with the olive oil and seasonings. Toss to thoroughly coat.
Add butter to a large cast iron skillet over medium heat. Once melted, add in the minced garlic and seasonings, followed by the coated potatoes, cut-side down.
Cook 3-5 minutes per side, or until fork-tender, turning when they just start to crisp/brown on one side. Using tongs, remove to a plate and cover with foil to keep warm. Be sure to leave the remaining oil/butter and seasonings for the steak.
Increase the temperature to medium-high heat and add the steak to the skillet - with the marinade. Allow the steak to sear for 30-60 seconds before stirring to continue cooking until golden brown. Approximately 1 minute per side or until the they reach desired doneness.
Right before the steak is done, add the potatoes back to the skillet to warm. Garnish with herbs, salt, pepper, and crushed red pepper flakes if desired.