In a large bowl, combine the cut rhubarb, quartered strawberries, 7 tablespoons maple sugar, arrowroot starch, and 1.5 teaspoons vanilla. Gently toss everything together until the fruit is evenly coated and the arrowroot starch is fully incorporated—this starch will thicken the juices as the fruit cooks and prevent a soggy crisp. Set the filling aside while you prepare the topping.

In a separate bowl, combine the coarsely chopped almonds, coconut flakes, almond flour, 1/4 cup maple sugar, 1 teaspoon vanilla, cinnamon, and salt. Drizzle in the slightly cooled melted coconut oil and mix with a fork or your fingertips until the mixture resembles coarse crumbs with some small clusters—I like to leave some texture variation rather than making it too uniform, which keeps the crisp from getting dense. Don't overmix or the oil will make everything too compact. Refrigerate this topping for at least 10-15 minutes while the oven preheats.

Preheat your oven to 350°F. Pour the fruit filling from Step 1 into a 9x13 inch baking dish (or similar size), spreading it into an even layer. Scatter the chilled topping mixture from Step 2 evenly over the fruit, breaking up any large clumps with your fingers as you go. Bake for 40-50 minutes until the fruit is bubbling around the edges and the topping is golden brown. I find that checking at 40 minutes prevents over-browning of the nuts and coconut while still ensuring the fruit cooks through.

Remove the crisp from the oven and let it rest for 5-10 minutes before serving. This resting time allows the filling to set slightly so it won't be runny when you scoop it, while still maintaining that warm, comforting temperature. Serve warm on its own or with your favorite paleo-friendly topping like coconut whipped cream or vanilla ice cream.