The story I've always heard is that this really was Queen Elizabeth's actual recipe and became popular in Canada in the 1950s when she was coronated. This makes some kind of sense because Tom's grandmother, Myrtle, was born in Moose Jaw, Saskatchewan. The instructions here follow the formatting of the recipe in my mom's recipe file.

Cake

• Pour 1 c. boiling water over 1 t. baking soda, 1 lb. dates. Let stand.
• Cream together 1 c. brown sugar, 1 egg, 1/4 c. butter, 1 T. vanilla.
• Measure 1 1/2 c. flour, 1/2 t. baking powder, 1/2 t. salt, 1/2+ c. chopped walnuts. ¹⁾
• Add all to date mixture.
• Bake 35 minutes in 9 x 12 inch baking pan at 350 degrees.

Frosting

• Mix together 10 T. (1/2 c. + 2 T.) brown sugar, 12 T. (3/4 c.) canned milk, 4 T. butter in saucepan. Boil 3 minutes.
• Frost while cake is hot; top with coconut.

• Myrtle Keays
• Seasons & Suppers

You can find many sources online for versions of this cake; they're fundamentally the same. I've included the link above because it is largely identical to Myrtle's recipe, but includes a variation that requires broiling the topping for a few minutes until golden brown.

Here's the ingredient list for comparison.

For Cake:

• 1 cup pitted dates, chopped and packed
• 1 teaspoon baking soda
• 1 cup boiling water
• 1/2 cup salted butter, at room temperature
• 1 cup light brown sugar, packed
• 1 large egg
• 1 teaspoon vanilla
• 1 1/2 cups all-purpose flour, spooned and levelled
• 1 teaspoon baking powder
• 1/2 teaspoon nutmeg, *see Note 2 below
• 1/2 teaspoon salt

Topping:

• 1/2 cup light brown sugar, packed
• 1/4 cup butter
• 3 Tablespoons heavy whipping cream, 35% b.f.
• 1/2 cup sweetened shredded coconut, packed