Arrange cubed bread in a single layer on a baking sheet. Brush lightly with olive oil, and place in the preheated oven for 5-8 minutes to dry out and brown. Toss half way through the cooking time. Remove from oven and set aside.
Lemon Parmesan Vinaigrette
Add olive oil, parmesan, lemon juice, garlic, Italian seasoning, red pepper flakes, black pepper and salt to a food processor and blend until the ingredients are emulsified. (You can also shake in a jar or whisk in small bowl.)
Garden Salad
Toss lettuce, tomatoes, cucumber, onion, radishes and sunflower seeds together. Pour dressing over salad. Toss again. Top with croutons and serve.
Video
Notes
In order for your bread cubes to dry out properly when making croutons, make sure they are in a single layer on the baking sheet with room in between the cubes so the heat can circulate and moisture can escape.
It really is important to finely grate your own Parmesan for the best salad dressing. The powdered stuff won't really combine with the other ingredients and will separate later.
Let your guests dress their own salad for a longer lasting salad.