Preheat oven to 350 degrees Fahrenheit. Line a 9×13-inch baking pan with Gefen Parchment Paper, leaving an overhang on the sides.

Cream the margarine, sugar, and brown sugar until smooth. Mix in the vanilla. Add the flour and salt, stirring until a soft, crumbly dough forms. Reserve one and a half cups of dough for the topping.

Press the remaining dough firmly into the bottom of the 9×13 pan. Prick lightly with a fork and bake for 14 to 16 minutes until set and pale golden. Leave the oven on.

Dissolve espresso powder in hot water. Whisk in the brown sugar, cinnamon, and flour, and melted margarine into a thick espresso paste.

Spread the cappuccino paste over the warm base. Mix the oats into the reserved one and a half cups dough to form coarse crumbs, then crumble evenly over the top.

Bake for 30 to 40 minutes until the crumb topping is deep golden and the filling bubbles around the edges.

Cool completely in the pan.

Whisk glaze ingredients, drizzle over top, and slice into 24 squares.