Bring sugar, coconut sugar, and water to a boil over high heat, stirring continuously until a syrup forms. There will be bubbles! It should take 3-5 minutes.
Reduce heat to medium and add the fennel seeds. Stir until the mixture crystalizes—it will be quick! (The fennel should look dry, but it will also dry a bit more as it cools.)
Remove pan from heat and stir another 30-40 seconds, until the fennel seeds dry and can separate.
Add to a dish to serve immediately or store in an airtight container for later.
Great on salads, desserts, oats, or as a breath freshener after a meal. Great for digestion!
Lasts 1-2 weeks stored in an airtight container.
Yields ⅓ cup candied fennel seeds.