1. Preheat oven to 350 degrees F. In a large mixing bowl, whisk together the oats, flour, both sugars, baking powder, baking soda and salt.
2. Add the chopped up cold butter and work it into the dry ingredients with your fingers or a pastry blender until the mixture looks like small crumbles. Reserve 1 cup of this mixture.
3. Dump the remaining crumb mixture into an ungreased 15” x 10” pan (jellyroll pan) and press it into an even crust.
4. Bake in 350 degree oven for 12-13 minutes or until it is firm to touch. Do not brown.
5. Remove pan from oven. Warm the jam in the microwave for 30 seconds and then stir in the lemon zest. Drizzle the warm jam over the warm crust. Spread the chopped strawberries over the crust. Sprinkle on the reserved cup of crumb mixture.
6. Return pan to 350 degree F oven and bake for another 20-25 minutes or until the crumbs on top are lightly browned. Then remove it from the oven and let the pan cool for 1 hour.
7. Melt the white chocolate in microwave, following directions on package. Drizzle melted chocolate in thin lines over the streusel top. Cut into bars.