Preheat the oven to 350° F. Generously butter a 9x9x2-inch metal baking pan. Line a rimmed baking sheet with parchment. Using on/off turns, blend the first crust 4 ingredients in your food processor until a coarse meal forms. Add the pecans; using on/off turns, and process until the nuts are chopped. Add the oats; process using on/off turns until the mixture is moistened but not clumping. Press 3 1/2 cups crumbs onto the bottom of the prepared square pan (do not clean the processor). Transfer the remaining crumbs to the lined baking sheet. Bake the crumbs on the baking sheet until golden, stirring once, about 8 minutes. Cool the crumbs. Bake the crust until golden, about 30 minutes. Remove the crust from the oven while preparing the filling. Maintain the oven temperature.
PREPARE THE FILLING:
Blend all of the ingredients in the same processor until smooth. Spread the filling over the warm crust; bake until set, dry in the center, and beginning to rise at the edges, about 20 minutes. Continue to maintain the oven temperature.
PREPARE THE TOPPING:
Mix all of the ingredients in a small bowl. Spread evenly over the hot filling. Bake until the topping sets and bubbles at the edges, about 5 minutes. Cool completely in the pan on a rack. Sprinkle the baked crumbs over the topping; gently press into the topping.
Lightly cover with plastic wrap; chill until cold, about 2 hours before slicing.
Notes
*These may be prepared up to 2 days ahead. Keep chilled. Cut into squares. The photos show them cut into 9 squares. You'll be happier cutting them into 16 squares as they are rich and perfect when served as a smaller bar.