Preheat oven to 375 F. Line an 8×8-inch baking pan with parchment paper with the parchment overhanging the edges of the pan. Set aside.
In a medium bowl, stir oats, flour, brown sugar, cinnamon, and salt together until combined.
Stir the melted butter into the oatmeal mixture until it forms clumps.
Set aside 1/2 cup of the crumble mixture.
Press the remaining oat mixture into an even layer in the bottom of the prepared pan.
In a small bowl, toss strawberries, sugar, corn starch, and lemon juice together.
Sprinkle the reserved crumbs over the fruit filling. The crumbs won't completely cover the fruit.
Bake the bars for 35-45 minutes, or until the topping smells is light golden brown.
Cool the bars in the pan until they reach room temperature.
To make the glaze, whisk powdered sugar, vanilla, and milk together until combined.
Drizzle over cooled bars, and cut into squares to serve.
Video
Notes
Oats: I haven't tried using quick oats in this recipe.
Flour: Feel free to substitute an equal amount of all-purpose flour for the white whole-wheat flour.
Strawberries: Frozen strawberries can be substituted for the fresh strawberries, but you may find that you need to make a couple of adjustments. First, you may need to add a few extra minutes to the baking time. Second, the filling may be thinner, so you might find that you need to add additional cornstarch to the filling to help it thicken properly.