If desired, roast the sunflower seeds: Preheat the oven to 325°F (160°C). Spread the seeds over a large rimmed baking sheet in an even layer. Roast for 9 to 12 minutes, until lightly golden in some spots.

Remove from the oven and set aside.

Increase the oven temperature to 350°F (180°C). Line a 9-inch (2.5 L) square pan (or an 8-inch/2 L pan for a slightly thicker bar) with parchment paper, leaving some overhang, which will make it easy to lift out the bars later.

In a food processor, combine the sunflower seeds, oats, and salt and process until you have a coarse flour.

In a small pot, melt the oil over low heat. Remove from the heat and whisk in the maple syrup, brown rice syrup, and sunflower seed butter until combined. Pour the wet mixture on top of the oat mixture in the food processor and process until the mixture comes together, 10 to 15 seconds. The dough should feel quite heavy and oily, and there shouldn’t be any dry patches. If there are, process for 5 seconds more. If for some reason it’s still too dry, try adding water, a teaspoon (5 mL) at a time, and processing again until it comes together.

Set aside 1¼ cups (300 mL) of the oat mixture for the topping. Crumble the remaining oat mixture over the base of the prepared pan in an even layer. Starting at the center, push down with your fingers (you can lightly wet them if they stick) to spread out and pack down the crust. Press the dough down tightly. Even out the edges with your fingertips. Prick the crust with the tines of a fork 9 times to allow steam to escape.

Prebake the crust for 10 minutes. Remove from the oven and let cool for 5 minutes. (If the crust puffed up while baking, gently press down on it to release the air.) Spread the jam in an even layer over the crust. Crumble the reserved 1¼ cups (300 mL) oat mixture evenly over the jam.

Bake, uncovered, for 14 to 18 minutes more, until the topping is lightly firm to the touch. The topping will not turn golden in color; it will remain the same shade as it was before baking. Let cool in the pan on a cooling rack for 45 to 60 minutes, then transfer the pan to the freezer for 30 minutes until completely cool. Lift out the slab and slice it into squares or bars. Leftovers can be stored in an airtight container in the fridge for several days, or wrapped up and stored in the freezer for 4 to 5 weeks.