Preheat oven to 350°F (175°C). Grease a 9x13 inch baking dish.
In a small saucepan, combine the honey substitute, water, cinnamon stick, lemon zest, orange zest, cardamom, and salt. Bring to a simmer over medium heat. Once simmering, remove from heat and let it steep for 15 minutes. Strain out the solids and discard them.
In a small bowl, mix together ground cinnamon, cloves, nutmeg, and granulated sweetener. Set aside.
Brush one sheet of phyllo dough with melted butter and sprinkle with the spiced sugar mixture. Repeat with the remaining sheets, stacking them on top of each other.
Use a sharp knife to cut the layered phyllo into 6 equal portions. Place each portion in the prepared baking dish, and bake for 20 25 minutes or until golden brown and crispy. Allow to cool completely.
Break the cooled phyllo stack into bite sized pieces. In a separate bowl, mix together almond milk and melted butter. Drizzle this mixture over the broken phyllo pieces, ensuring each piece is coated evenly.
Pour the prepared keto honey syrup over the soaked phyllo pieces until well saturated. Cover and refrigerate for at least 2 hours or overnight to allow the flavors to meld together.
Before serving, toast the chopped walnuts in a dry pan over medium heat for 3 4 minutes or until golden brown. Sprinkle over the top of the trifle.