To make the Irish whiskey butter, place the butter in a mixing bowl and whip until fluffy. With the mixer running, gradually add the confectioners' sugar. Slowly add the Irish whiskey until combined. The mixture may look separated and curdled at first but if you continue whipping, it will come together. Topping may be used at room temperature or chilled.

Preheat oven to 375 degrees F. Lightly grease a 7-by-11-inch baking dish and set aside.

In a medium bowl, combine the strawberries, rhubarb, sugar, cornstarch, and lemon juice. Toss to coat. Pour the strawberry mixture into the prepared baking dish.

In a medium, mixing bowl, add the flour, oats, light brown sugar, and salt, stirring to combine. Add the diced butter to the flour mixture, and using your fingers, work the mixture until it resembles coarse crumbs. Pour the crumb mixture evenly on top of the strawberry mixture.

Place the baking dish in the oven and bake for 40 minutes, or until the filling is bubbly and the topping is golden brown.

Serve warm with a spoonful of the Irish Whiskey Butter.