Toast the Pecans
Heat a large skillet over medium heat and add chopped pecans. Toast for 5–7 minutes, stirring often, until fragrant and golden. Set aside to cool.

Prepare the Custard Base
In a heavy saucepan, combine cream and milk over medium heat until small bubbles form around the edges. In a separate bowl, whisk egg yolks, brown sugar, salt, and cinnamon until smooth and slightly lightened.

Temper the Eggs
Slowly pour about ½ cup of the warm cream into the egg yolks, whisking constantly to prevent scrambling. Gradually add the rest of the cream while whisking, then return the full mixture to the saucepan.

Cook the Custard
Cook over medium-low heat, stirring constantly, until the custard coats the back of a spoon and reaches 170°F (8–10 minutes). It should be silky and thick enough to draw a line with your finger.

Make the Pecan Caramel
While custard cools, heat maple syrup and butter in a small saucepan until bubbling. Add toasted pecans and cook 2–3 minutes until glossy. Stir in graham cracker crumbs if using.

Chill Everything
Strain the custard through a fine-mesh sieve, stir in vanilla, and refrigerate at least 4 hours. Let the pecan caramel cool to room temperature, then refrigerate alongside the custard.

Churn and Combine
Churn the custard in an ice cream maker according to manufacturer directions. During the last 5 minutes, gradually fold in the pecan caramel to create swirls throughout the ice cream.