Step 1: Prepare the Crust
Preheat oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, leaving overhang.
In a large mixing bowl, combine oats, almond flour, and dark brown sugar.
Add diced butter and work into the mixture with your hands until it resembles coarse crumbs and holds together when pressed.
Press two-thirds of the mixture into the pan, pressing firmly to form an even crust.
Bake for 15 minutes or until lightly golden. Remove and set aside.
Step 2: Make the Strawberry Filling
In a medium saucepan, combine chopped strawberries, maple syrup, vanilla extract, and lemon zest.
Cook over medium-high heat for 10–12 minutes, stirring occasionally, until the mixture becomes thick and jammy.
In a small bowl, whisk lemon juice with arrowroot starch until smooth.
Stir the slurry into the hot strawberry mixture and remove from heat. It will thicken quickly.
Step 3: Assemble and Bake
Spread the strawberry filling evenly over the pre-baked crust.
Crumble the remaining oat mixture over the top.
Bake for 25–30 minutes, until the top is golden and the filling bubbles at the edges.
Cool completely in the pan for at least 2 hours. For cleaner cuts, refrigerate for 30 minutes before slicing.
Step 4: Serve
Cut into 12 bars using a sharp knife. Clean between cuts for neat slices.
Serve slightly warm, room temperature, or chilled with a dollop of Greek yogurt if desired.