In a small bowl, stir together butter, chives, thyme, and salt.
Spread approximately 1 tablespoon butter mixture each onto frozen bread slices. Layer radishes in a shingled pattern to cover butter layer. Using a sharp knife, trim and discard crusts from bread slices, and cut each slice in half diagonally.
Let bread thaw for 5 to 10 minutes before serving, or cover with damp paper towels, place in a covered container, and refrigerate for a few hours until serving time.
Just before serving, garnish with microgreens, if desired.
Notes
*We used Kerry gold.
**We used a mandoline on the1/32-inch setting.
Recipe by TeaTime Magazine at https://teatimemagazine.com/irish-butter-radish-canapes-recipe/