In a mixer fitted with a whisk attachment (or using a hand mixer), mix the flour, baking powder, sugar, and oats. In a medium bowl, mix the cream, corn syrup, melted butter, and vanilla. Add to the dry ingredients and mix just until combined. Set aside for 15 minutes. Keeping in mind that the cookies will spread until completely flat, drop the batter in heaping teaspoons onto nonstick sheet pans, spacing them out evenly. You can fit 6 cookies on a 14 by 17-inch pan. Bake until golden brown, 8 to 10 minutes. Let cool 2 to 3 minutes in the pan, then use a spatula to transfer to wire racks to finish cooling. To store, layer the cookies with waxed paper and store in an airtight container.
Ice Cream: In a cold bowl, mix the ice cream with ground cinnamon until desired taste. Return to freezer.
To assemble sandwiches, turn the cookies flat side up on a baking sheet lined with parchment. Using a mini ice cream scoop, scoop 2 balls of ice cream and place side by side on the flat side of a cookie. Top with a second cookie flat side down. Serve immediately or return to freezer.