How to Make It
Prepare the Filling: Stir together first five ingredients in a saucepan. Bring to a boil over medium-high, stirring occasionally. Reduce heat to medium-low; cook, stirring often, until thickened and reduced to 3 1⁄2 cups, 8 to 10 minutes. Cool completely, about 1 hour.
Prepare the Crumble: Preheat oven to 350°F. Spray a 13- x 9-inch baking pan with cooking spray. Line bottom and sides of pan with parchment, leaving a 2-inch overhang on all sides. Stir together flour, oats, brown sugar, almonds, cinnamon, and baking soda in a large bowl. Stir in melted butter until combined. Firmly press 4 cups of the Crumble mixture into bottom of prepared pan. Bake until lightly browned around edges, 10 to 12 minutes. Cool 5 minutes.
Spread cooled Filling over warm crust; sprinkle with remaining Crumble. Bake at 350°F until filling is bubbly, 35 to 40 minutes. Cool completely in pan, about 2 hours. Lift bars out of pan using parchment as handles. Slice into 32 bars.