Preheat oven to 180C/350F. Line a 9"x9" baking pan with baking parchment - leave enough overhang that you will be able use the paper to pull the s'mores bars out of the pan later.
In a stand mixer using the paddle attachment (or using a hand mixer) cream together the butter and sugar until pale and fluffy.
115 g (1 stick) unsalted butter, 125 g (⅔ cup) soft brown sugar
Beat in the egg, vanilla extract and almond extract (if using) until well combined, pale and creamy.
1 egg, 1 teaspoon vanilla extract, ½ - 1 teaspoon almond extract
Slowly mix in the flour, digestive or graham cracker crumbs, almonds, baking powder and salt until a dough is formed and no streaks of flour remain.
160 g (1 ¼ cups) all-purpose flour, 115 g (1 heaping cup) digestive biscuit/graham cracker crumbs, 30 g (¼ cup) almonds, 1 teaspoon baking powder, 1 teaspoon fine sea salt
Press ¾ of the cookie dough into the base of the prepared baking pan. Set aside the remaining dough until later.
Sprinkle the chocolate chips, cherries and then the marshmallows evenly over the top of the dough.
120 g (¾ cup) dark chocolate chips, 12 cherries, 75 g (1 ½ cups) mini marshmallows
Finish by dotting the remaining cookie dough over the top. This doesn't have to be neat! You won't be able to cover all of the toppings.
Bake for 20-25 minutes until golden on top. Leave to cool before cutting into 16 bars.