Step 1

Preheat the oven to 350ºF and grease a 8x8 inch baking pan well.

Step 2

In a large bowl, whisk together the almond flour, sweetener, coconut flour, and salt. Stir in the melted butter and vanilla until the dough begins to clump together.

Step 3

Press about two thirds of the dough into the prepared baking pan and bake 10 minutes. Remove from the oven and let cool 10 minutes to firm up.

Step 4

While the crust is baking, prepare the filling. Add the rhubarb, strawberries, sweetener, and water to a pan over medium low heat and bring to a simmer. Allow to cook until the fruit softens and begins to release liquid, about 5 to 8 minutes.

Step 5

Remove from heat and add the glucomannan, whisking briskly to combine. Allow to cool and thicken 10 minutes.

Step 6

Spread the filling evenly over the cooled crust and sprinkle the remaining crust mixture overtop. Bake another 20 to 25 minutes, or until the crust is light golden brown.

Step 7

Remove and let cool completely, then refrigerated one hour to firm up before cutting into bars.