Simmer carrots with broth, garlic, and lemon zest for 20 minutes or until tender.
Remove from heat.
In a blender, blend carrots and broth until smooth.
Add in half & half and juice of 1/2 lemon.
Stir to combine.
Add nutmeg, salt, and pepper to taste, checking seasoning as you go.
Pour back into pan and heat soup until just warm, then serve in bowls, garnished with spinach.