In a large skillet or Dutch oven, heat the vegetable oil over medium-high heat.
Add the beef tips in batches, browning them on all sides for about 3-4 minutes per batch. Remove the browned beef and set aside.
In the same skillet, add the chopped onion and sauté for 3-4 minutes until softened.
Add the minced garlic and cook for another 30 seconds until fragrant.
Return the beef tips to the skillet.
Pour in the beef broth, water, Worcestershire sauce, and soy sauce. Stir to combine.
Add the dried thyme, dried rosemary, black pepper, and salt. Stir well.
Bring the mixture to a boil, then reduce heat to low and cover the skillet.
Simmer for 1 hour, stirring occasionally, until the beef is tender.
In a small bowl, mix the cornstarch with cold water until smooth.
Gradually stir the cornstarch mixture into the skillet and cook for 3-5 minutes until the gravy thickens.
Remove from heat and let the beef tips cool completely before transferring to freezer-safe containers.
Label and freeze for up to 3 months.
To reheat, thaw overnight in the refrigerator and warm on the stove over medium heat until heated through.