Heirloom Tomato Salad with Feta Recipe

¼ cup chopped fresh basil

3 tablespoons lemon juice

2 tablespoons olive oil

2 teaspoons Dijon mustard

¼ teaspoon salt

⅛ teaspoon ground black pepper

4 large multicolor heirloom tomatoes

sliced

2 medium English cucumbers

sliced

⅓ cup crumbled feta cheese