My daughter discovered these on spring break and we have made them every weekend since.

For extra matcha flavor, you can add up to 1 more tablespoon of matcha powder, but start with 3 tablespoons if you’re serving kids or first-timers—the flavor and color are still bold without being too earthy. If you have picky eaters who are unsure about green desserts, cut the matcha down to 2 tablespoons and swirl in a handful of rainbow sprinkles on top after cooking for a more familiar look.

You can also swap the vanilla or yellow cake mix for a white cake mix if that’s what you have on hand; the color will be slightly lighter but still vibrant. Try mixing in 1/2 cup of chopped macadamia nuts along with the white chocolate for a little crunch, or drizzle the cooled blondies with melted white chocolate for an extra-special presentation when company comes over.

To make them slightly less sweet, use a butter cake mix if available and reduce the white chocolate chips to 1/2 cup. If you need to keep these dairy-free, use a dairy-free cake mix, coconut-based sweetened condensed milk, vegan butter, and dairy-free white baking chips, but be aware that the texture may be a bit softer—chill before cutting for cleaner slices.

For food safety, always melt the butter gently and avoid overheating it so it doesn’t splatter; keep the slow cooker on a heat-safe surface away from the edge of the counter, and don’t leave it running unattended if children are around. Check that your slow cooker reaches and maintains a safe cooking temperature (the center of the blondies should reach at least 160°F/71°C). Let the blondies cool on a stable surface, and make sure they are fully cooled before covering tightly to prevent condensation and potential spoilage. Discard any leftovers that have sat out in a very warm room for more than a few hours, and always store them in a clean, airtight container.