In a medium bowl with a hand mixer or in the bowl of a stand mixer, beat the softened butter and sugar together until fully combined and fluffy.
Beat the eggs in one at a time until fully combined. Add vanilla and combine.
Add the flour, baking soda, salt, cinnamon, and nutmeg. Mix until just combined. Add the oats and mix until combined.
Cover the dough and place in the fridge for 30 minutes.
Preheat the oven to 375°. Line a baking sheet with parchment paper.
Scoop about 2-3 tablespoons of cookie dough and roll into a ball. Place the ball on the baking sheet and press down slightly. Repeat with the remaining dough, leaving at least 2 inches between each cookie on the sheet. Note: you can use more dough to make bigger sandwiches.
Bake the cookies for 10 minutes or until golden brown. Remove from the oven and allow to cool completely on the cookie sheet.
Remove the ice cream from the freezer to allow it to soften just a bit.
Take a large scoop of ice cream and place it on the inside of one cookie. Place another cookie on top and press down to push the ice cream out to the edges. Immediately place the cookie in the freezer and repeat with the remaining cookies.
Store the cookies covered in the freezer until ready to eat.
If you are freezing for later, transfer the cookies into an air tight container, placing a non-stick parchment paper between them to prevent them from sticking to each other. you can also wrap them individually.