In a food processor, combine crushed crackers, cashews, and granulated sugar. Cover and pulse several times to form fine crumbs. Add melted butter, and cover and pulse several times to combine. Press mixture onto bottom and up sides of a 9-inch pie plate. Bake for 8 to 10 minutes or until fragrant and firm. Cool on wire rack. Note: If desired, gingersnap crumbs may be substituted for graham crackers, and pecans may be used instead of cashews, as per original, very old recipe.
In small saucepan, bring whipping cream just to boiling over med. high heat. Remove from heat; add chocolate chips (do not stir). Allow to stand 5 minutes. Stir until smooth, and pour evenly over bottom of cooled crust.
In med. saucepan, combine brown sugar, cornstarch, and salt. Whisk in about 1/2 C. of evaporated milk. Then whisk in egg yolks until combined. Whisk in remaining evap. milk and milk. Cook and stir over medium heat until thickened and bubbly. Remove from heat, and stir in 3 TB. butter and vanilla. Cover and keep warm.
Prepare brown sugar meringue. In large mixing bowl, beat egg whites with electric mixer on medium high speed until soft peaks form. Gradually add brown sugar and granulated sugar, 1 Tbsp. at a time. Beat on high until stiff peaks form.
Pour warm filling over chocolate layer in pie pan. Spread meringue over warm filling, sealing to edge of crust and swirling meringue into peaks. Bake for 15 minutes, or until meringue is firm and golden. Cool on wire rack for 1 hour, then chill for 4-6 hours before serving.