In a medium bowl, mix your dark brown sugar and low-FODMAP flour, breaking up any lumps
To the flour and sugar, whisk in 1 cup of the lactose-free whole milk and egg yolks until smooth. Set aside for now
In a large saucepan over medium-low, melt your granulated sugar. You want to do this carefully, while tipping the pan frequently to evenly distribute the heat. Be patient
When the edges begin melting, begin to swirl the saucepan gently to evenly melt all the sugar and continue cooking, without stirring, until it turns an amber color (3-5 minutes)
Remove from the heat, and gently add in the heavy cream, followed by the remaining 1/2 cup of milk. It will spatter and the sugar will harden, that is normal
Return the mixture to your heat (adjusting to medium-low as necessary) and stir gently until the sugar caramel is melted into the milk mixture (about another 3-5 minutes). It will be hard until the mixture warms, and then should combine well
Once this is incorporated, whisk in the prepared flour/milk liquid, a little at a time, so as not to cook the egg yolks
It will begin to thicken, keep whisking until it is starting to bubble and become thick (about 5 minutes). Adjust your heat as necessary
Remove from the heat, and stir in your salt, vanilla extract, and unsalted butter
Whisk until the butter is melted, and the mixture is smooth
Pour into the prepared pie shell and cover with plastic wrap just touching the surface
Place in the refrigerator and chill until firm, at least 6 hours, or overnight
Before serving, whip heavy cream to top (if desired) and garnish with butterscotch chips and caramel sauce
Notes
Although this recipe has not been lab tested, a single serving should be low-FODMAP based on the ingredients, using FODMAP data at time of posting
Low-FODMAP milks include almond milk, hemp milk. I prefer the lactose-free whole milk for this recipe. Feel free to add lactase drops to your products 24 hours prior to use
Heavy cream is low-FODMAP in about 1/4 cup servings. If you plan to top this pie with additional whipping cream, I suggest you use lactase drops (mentioned above) to reduce the lactose. Altertnatively, canned coconut cream (dairy-free) may be substituted if desired, but this product can be more difficult to whip. See my recipe for low-FODMAP Vanilla Bean Coconut Whipped Cream for details!