Heat a large skillet with tall sides over medium heat. Add 1 tbsp of the avocado oil and 2 really large handfuls of baby spinach (or as much as you can fit into the skillet), cook, gently tossing/folding the spinach until it is slightly wilted. You don’t want it completely soggy/cooked yet-- just sorta cooked. Transfer the slightly wilted spinach to a colander and set in the sink. Continue to slightly wilt your spinach in batches, adding oil as needed, until all of your spinach is in the colander. Keep the colander in the sink while you prepare the cream sauce.
Add 1 more tablespoon of avocado oil to the same skillet along with the garlic and pepper flakes (if using) and cook, stirring, until the garlic is fragrant but not burnt-- about 1 minute. Pour in the coconut milk and bring to a light simmer.
Meanwhile, in a small bowl whisk together the broth and arrowroot flour until well combined to make a slurry.
Pour the slurry into the skillet and whisk to combine. The sauce will thicken very quickly (about 1 minute). When thickened, reduce the heat to low and add the wilted spinach into the sauce and fold to combine. (You’re going to think it’ll be too thick-- but just trust me ok… I know the sauce is gummy looking but the juices/water from the spinach helps loosen it up with time).
Stir in the lemon juice and leave the skillet on low, stirring occasionally, while you cook your scallops.