Cream the butter and sugar

• Cream the softened butter and sugar together well.
• Add the eggs, vanilla extract and heavy cream and mix until combined.

Make the dough

• In another bowl, whisk together the flour, cream of tartar, baking soda and salt.
• Add the wet mixture to the dry ingredients and mix without overmixing.
• Spread the dough into a rectangle and chill in the fridge.

Prepare the cinnamon spread

• Mix the softened butter, brown sugar, cinnamon and cornstarch together.

Fill and roll the dough

• Spread the cinnamon mixture over the semi-chilled rectangle, leaving an inch free at the top.
• Roll the dough tightly into a log and chill.

Shape the cookies

• Cut the log into equal pieces, like a cinnamon roll.
• Gently flatten each piece into a puck and roll it in cinnamon sugar.

Bake

• Place the cookies on a baking tray and bake at 350 °F (175 °C), depending on their size.

Make the glaze and finish

• Whisk the powdered sugar, water, vanilla and a pinch of salt into a glaze.
• Drizzle the glaze over the cooled cookies.