Melt 1 Tbs butter in non-stick skillet over medium-high heat.
Add garlic and cook until fragrant, about 30 seconds.
Add spinach and stir until wilted.
Transfer spinach to platter and cover to keep warm.
Wipe out skillet and return to heat. Add remaining butter. When butter is melted, and just begins to sizzle, add half the scallops and cook until browned, about 2 minutes. Transfer to platter.
Repeat with remaining scallops.
Carefully add lemon juice to pan, scraping up any brown bits from bottom of pan.