- Preheat your oven to 350°F (175°C) and grease an 8x8-inch baking pan or line it with parchment paper for easy removal. 
- In a large mixing bowl, combine the rolled oats, whole wheat flour, brown sugar, baking powder, and salt. Stir until well mixed. 
- In a separate bowl, whisk together the melted butter, honey (or maple syrup), and vanilla extract until smooth. 
- Pour the wet ingredients into the dry ingredients and mix until just combined. The mixture will be crumbly. 
- Reserve about 1 cup of the oat mixture and press the remaining mixture firmly into the bottom of the prepared baking pan to form a crust. 
- In another bowl, combine the chopped strawberries and lemon juice, then spread the strawberry mixture evenly over the crust. 
- Crumble the reserved oat mixture over the strawberries, covering them completely. 
- Bake for 25-30 minutes or until the top is golden brown. 
- Allow the bars to cool in the pan for at least 15 minutes before slicing into squares. For best results, chill in the refrigerator for an hour before serving.