In a small bowl, whisk together the salad dressing ingredients: olive oil, Ribena, lemon juice, fresh mint and pepper.
Toasting the almonds is optional, but it does intensify their flavour. To toast, place the almonds in an ungreased saucepan over medium heat. Stir them often, so they don't burn. They are done when golden brown. This should take about 5 minutes.
Place the spinach, blueberries, almonds and feta cheese in a large bowl.