From America's Test Kitchen Season 5: Appetizers
Spinach dip made with sour cream and soup mixes are flat, overly salty, and stale tasting. We wanted to ditch the mix and create a rich, thick, and creamy spinach dip brimming with big, bold flavors.
We were surprised to discover that frozen spinach actually made a better-tasting dip with a vibrant, more intense flavor than one made with fresh spinach. We used a food processor to chop the spinach and then enriched it with sour cream, mayonnaise, and a mixture of fresh herbs and seasonings. The only problem was that our dip, which took just about 15 minutes to make, took almost two hours to chill. Fortunately the solution turned out to be a simple one. Instead of thawing the spinach completely, we only partially thawed it, allowing the chunks of icy spinach to thoroughly cool the dip as they broke down in the food processor. This dip is fresh-tasting, quick to make, and ready to serve immediately.
Makes about 1 1/2 cups
Partial thawing of the spinach produces a cold dip that can be served without further chilling. If you don't own a microwave, the frozen spinach can be thawed at room temperature for 1 1/2 hours then squeezed of excess liquid. The garlic must be minced or pressed before going into the food processor; otherwise the dip will contain large chunks of garlic.