Step 1 - Preheat oven to 375°F and line a sheet pan with parchment paper. Slice off beet root ends and greens and scrub well under cold water. Peel skin from beet and cut beets into 1/4" cubes - if using different coloured beets, keep separate to avoid colours bleeding. Drizzle beets with 1/2 tbsp of Lemon Olive Oil and wrap each set of coloured beets in aluminum foil and bake 40-45 minutes or until tender. Remove from oven and cool.
Step 2 - Brush 3 tbsp olive oil on baguette slices. Bake 5 to 7 minutes or until golden brown. Add Cherry Balsamic to a non-stick pan and simmer over medium heat for 5-6 minutes until begins to thicken. Remove from heat.
Step 3 - in a small bowl, gently whisk together remaining olive oil and goat cheese, then spread toasted baguette slices with goat cheese. Remove reserved beets from foil with a slotted spoon, and arrange over goat cheese. Sprinkle with walnuts and drizzle with reduced balsamic. Sprinkle crostinis with fleur de sel and black pepper before serving at room temperature.