Heat the oven to 350°F (175°C) and line a baking dish with parchment paper.

In a large mixing bowl, combine oats, almond flour, salt, and lemon zest (if using). Stir in the melted coconut oil and maple syrup, then mix until the texture is crumbly yet holds together when pressed.

In a small saucepan, cook the raspberries with 1 tablespoon of maple syrup over medium heat. Stir frequently until the mixture thickens into a jam-like consistency, about 5-7 minutes.

Press half of the oat mixture into the bottom of the baking dish to create a crust, then evenly spread the raspberry filling on top.

Spread the remaining oat mixture evenly over the top and gently press it into place.

Put the dish in the oven and bake for 25-30 minutes, or until the topping turns golden brown and the filling begins to bubble.

Let the bars cool completely in the dish before slicing them into squares. This gives the bars time to set, making it easier to cut them into clean, even slices.