Position your oven rack in the middle and preheat to 350°F. While the oven heats, finely chop the strawberries into roughly 1/4-inch pieces and slice the rhubarb into thin 1/4-inch half-moons—keeping them uniform in size ensures even cooking throughout the muffins. Line your muffin pan with paper liners. Chop the almonds roughly for the topping and have all ingredients measured and ready before you begin mixing.

In a medium bowl, whisk together the almond flour, arrowroot, baking soda, salt, and ground cinnamon. This ensures the leavening agent and salt are evenly distributed throughout the flour base, preventing any pockets of baking soda that could create unpleasant metallic flavors. Set the dry mixture aside.

In a separate bowl, whisk together the room-temperature eggs, honey, vanilla, and lemon juice until well combined and slightly frothy—this incorporates air into the batter, which helps the muffins rise and achieve a tender crumb. The room-temperature eggs mix more easily and create a smoother batter.

Pour the wet ingredient mixture from Step 3 into the bowl with the dry ingredient mixture from Step 2, then gently stir until just combined. I like to fold rather than vigorously mix at this stage—overmixing develops gluten in almond flour, which can make the muffins dense and tough. Stop as soon as you don't see streaks of dry flour.

Gently fold the chopped strawberries and sliced rhubarb from Step 1 into the batter using a spatula, being careful not to overwork the batter. Divide the batter evenly among the lined muffin cups, filling each about three-quarters full. The batter will rise slightly as it bakes, so don't overfill.

Sprinkle the roughly chopped almonds evenly over the top of each muffin, then sprinkle the coconut sugar over the almonds. This creates a pleasant textured topping that won't burn in the oven. Bake for 22–26 minutes, until a toothpick inserted into the center of a muffin comes out with just a few moist crumbs (not wet batter). The muffins should be golden-brown and spring back when lightly touched.

Remove the muffin pan from the oven and let the muffins cool in the pan for about 5 minutes, then transfer them to a wire rack to cool completely. This prevents the bottoms from becoming soggy from condensation while still allowing air circulation.