Mix the seasoning/thickening ingredients in a small bowl; set aside.
Heat a large skillet over medium-high heat. Add the oil and heat.
Add the sliced meat. Cook over medium-high heat until the meat is browned on all both sides.
Add the garlic, onion and mushrooms. Cook until onion just begins to get soft–about 5 minutes.
Add the peppers and the 1/2 cup water. Bring to boil, reduce heat to low. Cover and cook for 5 minutes, or until peppers are crisp-tender and are bright colors.
Stir the seasoning/thickening mixture so everything is blended well. Add to the beef/pepper mixture in the skillet and cook until thickened and juice begins to bubble.
Serve over jasmine rice.