Mixed Greens with Beets and Garlic Croutons

8 cups mesclun greens (dandelion leaves, arugula, baby lettuces, chervil, watercress, wild chicory, and/or radicchio)

4 medium beet s (about 1 pound) or one 16-ounce can thin beet strips, rinsed and drained

1/3 of a 16-ounce loaf sourdough bread , cut into 3/4-inch slices

Salt

8 baby beet s

1/2 cup bottled red wine vinaigrette

2 tablespoons butter (no substitutes)