- Prep all ingredients per the instructions above. 
- In a large heavy-bottomed pot or sauté pan, heat olive oil over medium-low heat. Add onion and stir to coat with oil. Spread onions evenly over the pan and cook for about 15 minutes, stirring occasionally, until caramelized. 
- Once onions are nearly caramelized, add garlic and sauté until light golden brown. Add the mushrooms. Cook until tender, about 5–7 minutes. Stir in thyme, black pepper, salt. 
- Add in the shrimp and saute until firm to an internal temperature of 145°F / 63°C. 
- Boil spaghetti according to package instructions. Reserve at least 1/2 cup of pasta water per serving. 
- Add reserved pasta water in small increments if needed for moisture. Toss in the spaghetti and baby spinach until pasta is evenly coated and spinach wilts. 
- Whisk together vinaigrette ingredients and set aside. 
- Portion salad ingredients, then drizzle with prepared vinaigrette. 
- To make chia fresca, combine all the ingredients. Let sit for a few minutes to allow chia seeds to bloom. 
- Serve the spaghetti alongside salad and chia fresca.