2 small fresh fennel bulbs, trimmed of tough outer leaves, bulbs thinly sliced lengthwise with core intact, small fronds reserved for garnish
2 small turnips, peeled, each cut into 1/2-inch-thick wedges
Stir fennel seeds in small dry skillet over medium heat until very fragrant and slightly darker in color, about 3 minutes. Add coarse salt; stir to blend. Remove from heat; cool. Transfer fennel seed mixture to spice mill; grind until fennel seeds are just coarsely chopped (do not grind to powder). DO AHEAD: Can be made 2 days ahead. Store airtight at room temperature.
Arrange fennel slices and turnip wedges on platter; garnish with fennel fronds.