Set a large lidded skillet, preferably 12 inches wide, over medium heat.

Add 1 tablespoon of the olive oil to the skillet and swirl to coat the bottom.

Put the bread slices in the skillet in a single layer. Work in batches if they do not all fit at once.

Toast the bread for 1 to 2 minutes per side, until golden and crisp at the edges.

Transfer the toast to a plate and rub the top of each warm slice lightly with the whole garlic clove.

Set the garlic toasts aside for serving.

Add the remaining 1 tablespoon olive oil to the same skillet and keep the heat at medium.

Add the chopped onion and the 1/2 teaspoon kosher salt to the skillet.

Cook the onion for 4 to 5 minutes, stirring often, until it is soft and no longer looks raw.

Add the chopped garlic to the skillet and stir for about 30 seconds, just until it smells fragrant.

Add the thawed, squeezed spinach to the skillet. Use a spoon to break up any clumps.

Cook the spinach for 2 minutes, stirring, until it is hot all the way through and mixed evenly with the onion.