- 1 tablespoon butter, or more to taste
- 1 tablespoon olive oil
- 1 small yellow onion, chopped
- 1 large clove garlic, minced
- 2 large English cucumbers, peeled and thinly sliced
- 2 small zucchinis, peeled and thinly sliced
- 3 cups vegetable broth
- Melt butter with the oil in a large saucepan over medium-high heat. Cook and stir onion and garlic in the butter mixture until tender, 3 to 5 minutes. Add cucumber and zucchini slices; cook and stir until softened, 2 to 3 minutes. Pour vegetable broth over the mixture; bring to a boil, reduce heat to medium-low, and let simmer until the vegetables are cooked through, 20 to 25 minutes. Remove from heat and cool a few minutes.
- Pour soup into a blender no more than half full. Cover and hold lid in place with a towel; pulse a few times before leaving on to blend. Puree in batches until smooth.