Preheat oven to 400˚. Wash and toss beets with olive oil. Place in a roasting pan, cover with foil, and bake until beets are tender, 45-55 minutes (depending on size). Test by inserting a knife- if it's easy, they are done. Remove from oven and let cool.
Once beets have cooled, peel off skin and cut beets into 1/4" cubes. Set aside.
Remove avocado from skin and cut into 1/4" cubes. Place avocado in a bowl and combine with feta cheese. In a small bowl, whisk together olive oil, lemon juice, honey, and salt. Pour over avocado.
Take endives and cut off bottom stem. Carefully peel leaves off and place on a serving tray. Scoop 3-4 beet cubes and follow with a spoonful of avocado. Serve immediately.