1. Prepare the Candied Oranges:

• In a large pot, combine water and granulated sugar; bring to a simmer.
• Add thinly sliced oranges, cover, and simmer for 45 minutes.
• Remove slices, pat dry, and lightly sprinkle with granulated sugar.

2. Make the Graham Cracker Crust:

• Beat softened butter until smooth.
• Add brown sugar and honey; beat until creamy.
• Mix in flour, graham cracker crumbs, salt, baking powder, and cinnamon until dough forms.
• Add milk and mix until combined.
• Wrap dough in plastic wrap; chill for at least 30 minutes.
• Roll out dough on parchment paper to fit a 14″ x 5″ tart pan.
• Transfer dough to pan, press into place, trim excess, and prick the bottom with a fork.
• Bake at 350°F (175°C) with pie weights for 10-12 minutes, or until golden brown.

3. Prepare the Champagne Filling:

• In a small bowl, combine unflavored gelatin with cold water; let it bloom.
• In a saucepan, mix champagne, orange zest, and granulated sugar; heat until just simmering, then remove from heat.
• Microwave gelatin for 10 seconds; whisk into the warm champagne mixture until smooth.
• Let the mixture cool to room temperature until it begins to set.
• Whip heavy cream and powdered sugar to stiff peaks; fold in the champagne mixture gently.

4. Assemble the Tart:

• Spread the champagne filling evenly into the cooled graham cracker crust.
• Arrange candied orange slices on top.
• Refrigerate for 3-4 hours until set.