Heat the olive oil over medium heat in a large pan.
Add the frozen shrimp and cook for about 8-10 minutes. It should be pinkish in color, or 120 degrees Fahrenheit internally. Set aside.
Add the remaining 2 Tbsp. oil to the pan, and when heated add in the onion, stirring frequently. After 2 minutes add in the garlic and cook for 1 minute longer.
Constantly stirring, add in the arrowroot powder into the mixture and coat everything.
Turn up the heat a couple of notches, then slowly add in the milk, stirring constantly. Allow it to thicken and re-boil before each addition.
Repeat the same process with the broth.
Lower the heat back to medium. Add in the mustard, lemon juice, and spices, then mix thoroughly.
Add in the shrimp, sun dried tomatoes, and spinach. Mix everything together and let simmer for 2 minutes, allowing the spinach to wilt and the flavors to all mix.
Serve and enjoy!