Coat a 9-by-13-inch baking dish with cooking spray. Line the pan with 2 crisscrossed pieces of parchment paper or aluminum foil, leaving an overhang on all sides. Coat the parchment or foil with spray.

Combine the sunflower seed butter, dates, chocolate, olive oil, honey and vanilla in a small saucepan over medium heat. Stir, pressing with a rubber spatula to flatten the dates a bit, until the sunflower seed butter and chocolate are melted and the mixture is smooth, 2 to 3 minutes. Set aside to cool slightly, about 5 minutes.

Place the oats, pumpkin seeds, sunflower seeds, and 1 1/2 teaspoons of the flaky salt in a large bowl and stir to combine. Pour in the sunflower seed butter mixture and use the rubber spatula to press and fold until the oat mixture is evenly moistened (the mixture will be thick; you may need to use your hands).

Transfer to the prepared pan. Using a flat-bottomed measuring cup, press the mixture into an even layer, spreading all the way to the edges. Sprinkle with the remaining 1/2 teaspoon flaky salt. Freeze until cold to the touch and very firm, 40 to 45 minutes.

Using the paper or foil overhang, lift the slab out of the baking dish onto a cutting board. Cut into 18 bars. Wrap each bar individually in plastic wrap and store in the refrigerator. Alternatively, refrigerate the bars in an airtight container.

Recipe notes

1. Refrigerate the bars for up to one week.

2. If you start with raw, unsalted pumpkin and sunflower seeds, roast at 350 F until lightly golden, about 10 minutes first. If you would prefer not to buy both, you can make these with all pumpkin or all sunflower seeds. Add 1/4 teaspoon more flaky salt to the bars.

3. Creamy, sugar-free nut butters can be substituted for sunflower seed butter.

4. To make these vegan, use maple syrup instead of honey.

(Grace Elkus is senior food editor for TheKitchn.com, a nationally known blog for people who love food and home cooking. Submit any comments or questions to editorial@thekitchn.com.)