Preheat oven to 375°F. Line a 9x13-inch baking pan with foil, making sure there is overhand on either side to easily lift up the bars later, and grease lightly with cooking spray. Set aside.

To make the crust, in a large bowl, whisk together the flour, sugar, baking powder and salt. Add the butter and work it in with your fingers until it resembles coarse crumbs. Add the beaten egg and mix with a rubber spatula until it roughly comes together. Transfer to the prepared pan and press it down firmly into an even layer. Bake until lightly golden brown, about 18 to 20 minutes. Remove from the oven and let cool.

To make the filling, in a large heavy saucepan, combine the honey, brown sugar, and salt. Set over moderate heat and bring to a boil, stirring frequently to dissolve the sugar. Boil for 2 minutes without stirring, and then stir in the butter and cream. Cook and stir for one minute, or until smooth. Remove from the heat and add in the vanilla, nuts, seeds and flax meal. Stir until evenly combined and everything is coated well.

Immediately pour into the baked crust and spread out into an even layer. Bake until the topping is bubbly, about 15 to 20 minutes. Remove from the oven and allow to cool completely on a wire rack. once cooled, using the excess foil, lift up the slab from the pan. Cut into 24 bars and serve immediately. Leftovers can be stored in an airtight container in the fridge for up to 1 week. Just allow to come to room temperature before serving. Enjoy!