To make these Homemade Maple Butter Tarts gluten-free. Substitute the all-purpose flour. With a gluten-free flour blend. Additionally, ensure your tart shells are gluten-free. Many stores offer pre-made gluten-free tart shells. Or you can make your own. Using a gluten-free flour mix. Verify that all other ingredients, like the vanilla extract and raisins. Are certified gluten-free. To avoid cross-contamination. With these simple swaps. You can enjoy these delicious tarts. Without any gluten worries.