Start by making a flax egg. Combine the ground flaxseed with cold water, stir and set aside.
Add the dry ingredients (flour, oats, almonds, baking powder, speculoos spice mix, salt, orange zest) to a large mixing bowl and stir to combine.
Melt the almond butter and agave syrup in the microwave or over medium heat. Then add to the dry ingredients.
Add in the flax egg and plant-based milk and mix to form a dough. Using your hands might be easier here. Form a disc, wrap in cling film and place in the fridge for 30 minutes.
Preheat your oven to 180°C/350°F. Roll out the dough between parchment paper and cling film to about 1 cm thick. Cut out the cookies and place on a baking tray lined with parchment paper.
Bake the speculoos cookies for ~10 minutes. Carefully watch them as they burn easily. Remove from the oven and let cool before serving.