Preheat the oven to 350°F/180°C.

Line a 9 by 13-inch/23 by 33cm baking pan with parchment paper.

Combine the butter or coconut oil, almond butter, and brown rice syrup or maple syrup in a large bowl and, using a wooden spoon, mix well.

Add the rolled oats, almond flour, oat flour, sugar, baking powder, salt, vanilla and almond extracts, and cinnamon to the butter mixture and stir until a soft dough forms. Divide the dough into thirds. Press two-thirds of the dough into the bottom of the prepared pan and reserve the remaining one-third for the topping.

Stir together the jam, lemon juice, and salt and then spread the mixture evenly over the bottom crust.

Crumble the remaining one-third dough over the jam filling.

Bake the jam bars until golden brown around the edges, about 35 minutes. Let the pastry cool completely in the pan on a wire rack before cutting into bars.

The jam bars will keep, well wrapped, at room temperature for up to 4 days.