Add all Mandarin teriyaki ingredients EXCEPT mandarin orange slices and corn starch slurry to a medium sauce pot. Tip: It helps to heat up honey so it pours easier. Set pot to simmer for half hour.
In another medium pot, add 2 cups basmati rice and 2-3/4 cups of cold water, cover with lid. Bring to boil then reduce to low once boiling. Once all water is absorbed, turn off burner and leave lid on.
To finish teriyaki sauce, add mandarin oranges along with corn starch slurry. (For slurry, start with 2 teaspoons of corn starch added to a mixing bowl, then drizzle in water and mix by hand until liquid). Stir thoroughly and allow to simmer for 20-30 minutes. For thicker sauce, add 2 more teaspoons of corn starch slurry (or more).
In a wok or large cast iron skillet, heat a thin layer of oil on medium-high. Once oil surface temp reaches 500 degrees Fahrenheit, add onion, carrots, and broccoli and lightly salt and pepper.
Toss or stir until all vegetables are seared and slightly soft. Remove and set aside on a plate. Add another thin layer of oil then toss in pheasant, lightly salt and pepper.
Toss or stir pheasant until seared and thoroughly cooked. Add vegetables back along with sliced mushrooms. Stir and oil lightly if necessary, stir until mushrooms are slightly cooked.
To finish dish, add sauce to pan or wok with vegetables and pheasant, toss thoroughly then plate rice and top with pheasant and vegetables, ladle over extra sauce. Garnish with crushed cashews and sliced green onions.