Heat olive oil in a large skillet over medium-high heat.
Add beef tips in batches and brown on all sides, about 3-4 minutes per batch. Remove browned beef tips and set aside.
In the same skillet, add diced onion and cook until translucent, about 4 minutes.
Add sliced mushrooms and cook until they release their moisture and begin to brown, about 6 minutes.
Stir in minced garlic and cook for 1 minute until fragrant.
Return the beef tips to the skillet.
Add beef broth, tomato paste, Worcestershire sauce, dried thyme, dried rosemary, black pepper, and salt. Stir to combine.
Bring the mixture to a simmer, then reduce heat to low and cover. Cook for 30 minutes, stirring occasionally, until beef is tender.
In a small bowl, whisk together cornstarch and 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 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 stovetop over medium heat until heated through.