Preheat your oven to 375°F and position the rack to the middle of the oven. This ensures even baking of both the fruit filling and the crispy topping. Pro tip: Starting with a preheated oven prevents the fruit from releasing too much liquid before the topping has a chance to cook.

Prepare your fruit: wash and hull the strawberries, then cut them in half. Cut the rhubarb into 1-inch pieces, discarding any leaves (which are toxic). If your rhubarb pieces are particularly thick, cut them lengthwise first to ensure even cooking. Pro tip: Rhubarb leaves contain oxalic acid and should never be consumed, so discard them completely.

In a large mixing bowl, combine the prepared strawberries and rhubarb. Sprinkle the granulated sugar, cornstarch, lemon juice, and sea salt over the fruit. Pro tip: The cornstarch is crucial in a strawberry rhubarb crisp—it absorbs excess liquid without making the filling taste starchy or weird.

Gently toss the mixture until everything is evenly coated. Try not to crush the strawberries; you want some texture in your finished dessert. Let the filling sit for 5 minutes to allow the sugar to start dissolving. Pro tip: This short wait helps the filling develop more flavor and prevents the crisp topping from burning before the fruit cooks through.

Pour the fruit mixture into your prepared 9x13 inch baking dish, spreading it evenly into a single layer. The fruit should fill the dish about three-quarters full. Pro tip: A slightly overfilled dish is fine—the strawberry rhubarb crisp topping will settle as it bakes.

In a medium mixing bowl, whisk together the rolled oats, all-purpose flour, brown sugar, and sea salt. If you're adding cinnamon or other spices, mix them in at this point. Pro tip: Using old-fashioned rolled oats instead of instant oats gives this rhubarb crisp topping the best texture—chewy in the middle and crispy on the edges.

Add the cold butter cubes to the dry ingredients. Using a pastry cutter, two forks, or your fingertips, work the butter into the mixture until it resembles coarse breadcrumbs. This should take about 2-3 minutes. Pro tip: Cold butter is absolutely essential here—it creates pockets of steam that make the topping crispy rather than dense. If your kitchen is warm, refrigerate the butter cubes for 10 minutes before using.

Sprinkle the crisp topping evenly over the fruit filling, pressing down very gently so it holds together slightly but remains somewhat loose. An easy strawberry rhubarb crisp should have a rustic, chunky topping, not a smooth crust. Pro tip: Don't press too firmly—you want the topping to stay airy and crispy, not compact into a dense layer.

Place the strawberry rhubarb crisp in the preheated 375°F oven for 35-40 minutes, until the topping is golden brown and the fruit filling is bubbling around the edges. Pro tip: Every oven is slightly different, so start checking at 35 minutes. The top should be deep golden brown, not pale.

Remove from the oven and let it cool for 10-15 minutes before serving. This resting time allows the filling to set slightly, making it easier to serve without it being too runny. Pro tip: If you serve it too hot, the filling will be very liquid; too cool and you'll miss that wonderful warm, gooey texture that makes this homemade rhubarb crisp recipe so special.

Scoop generous portions of the strawberry rhubarb crisp into bowls or onto plates. Top with a dollop of vanilla ice cream, whipped cream, or Greek yogurt for the ultimate experience. Pro tip: This fruit crisp recipe is even better when served warm, but it's also delicious at room temperature or straight from the refrigerator.