- In heavy-bottomed sauce pan set over medium-high heat, melt butter and bring to a boil. Butter will separate into butterfat and milk. Once milk has entirely boiled away, milk solids will begin to brown. As soon as browning begins, remove pan from heat and carefully stir hot butter fat so toasted milk solids swirl up and season the fat. Note: As butterfat cools, it should turn dark brown in color. If it turns black, discard, as that means it is burnt butter, which is no fun.
- While browned butter is cooling, whip remaining ingredients together in blender. Once smooth, turn blender speed to low and slowly pour in room-temperature browned butter. Reserve the filling in refrigerator until ready to use.
- In medium bowl, whisk together egg yolks and heavy cream.
- In larger bowl, mix together dry ingredients and then slowly work chilled butter in by hand (this may also be done in food processor, just be careful not to overwork dough as it will become tough). The texture should be crumbly, like a very coarse meal.
- Fold egg and cream mixture into dough until just incorporated, but still a bit crumbly. Wrap dough and place in refrigerator to rest for 20 minutes. (This allows glutens to relax and flour to hydrate.)
- Preheat oven to 375 degrees.
- Roll half of dough out on lightly floured work surface to ¼-inch thick. Line 9-inch tart mold with rolled crust. Repeat with other half in another 9-inch tart pan. Note: To ensure a nice shape, rest dough-lined pans in freezer for 5–10 minutes. Once cold, cut away excess from edges with sharp knife and evenly prick bottom of shells with fork. Line shells with parchment or wax paper and fill with pie weights.
- Bake 18 minutes or until golden brown around edges. Allow to cool completely before removing parchment paper and weights. Fill prebaked shells to brim with prepared banana custard and bake for 18 minutes, or until custard is firm and set in center. Tart may be served room temperature or warm.
- Combine all ingredients except sugar and egg yolks in nonreactive pot and set over medium-high heat. Stir occasionally to prevent sticking while mixture comes to a simmer, then reduce heat to low and allow spices and coffee to steep 10 minutes.
- Turn heat back to medium-high and bring mixture back to a light simmer.
- In medium bowl, whisk together sugar and egg yolks. Carefully whisk 2 cups of hot ice cream base into sugar and egg mixture. Once fully incorporated, stir egg and sugar mixture back into remaining mix in pot.
- Remove pot from heat, mix vigorously with whisk, and pour through strainer to remove spices and coffee grinds. The base can now be added to an ice cream machine and processed according to manufacturer’s instructions.
To Assemble and Serve
- Cut each tart into 6 even slices; dust liberally with powdered sugar and serve with ice cream.