Cut the small onion into half rings and finely chop the garlic.
Heat oil in a pan over medium-high heat. Sear the marinated neck steaks for 2 minutes on each side until browned. Transfer to a plate and reduce heat to medium.
In the same pan, add the onion rings and garlic and cook for 2 minutes, stirring occasionally, until softened. Stir in the 1 tablespoon of marinade and cook for 1 minute. Pour in the cream and stir well, scraping up any browned bits from the bottom of the pan.
Return the steaks to the pan and bring to a simmer. Simmer for 5 minutes, stirring occasionally, until the sauce thickens. The steaks should reach an internal temperature of 63°C (145°F).