Line 10x15-inch rimmed baking sheet with parchment paper.

In medium bowl, whisk together the flax egg, peanut butter, melted butter, maple syrup and vanilla until smooth.

Stir in gluten-free flour and salt until dough forms.

Transfer dough to parchment-lined baking sheet. Press or roll the dough into a 1/4-in thick rectangle. Freeze for at least 40 minutes.

Cut cookie dough in half vertically so you have two equal layers.

Spread strawberry ice cream evenly over one half of frozen peanut butter cookie dough. Gently place other half of cookie dough on top to form sandwich.

Freeze bars for at least 2 hours to firm up.

Remove from the freezer and cut into squares or bars.