In a medium bowl, whisk together the flour, panko, brown sugar, salt and cinnamon until the mixture is well-combined.

Then pour in the melted butter and whisk until the mixture is totally moistened by the butter, leaving no dry flour bits.

Refrigerate the crisp topping until we are ready to use it.

Position an oven rack in the middle position and preheat the oven to 375 degrees.

Combine all of the filling ingredients in a large bowl and mix well.

Transfer the fruit mixture to a 10-inch oven safe skillet. Heat the fruit mixture over medium-high heat and stirring frequently, cook the mixture until the fruit has released most of its liquid and the liquid nearly covers the softened fruit. Taste test a piece of rhubarb to ensure it has softened.

Cut the heat and pull the crisp topping out of the fridge.

The butter in the crisp topping will have started to firm up, this is perfect because we want to clump it up and break it into irregular sizes and shapes to top the fruit.

Sprinkle the crisp topping over the whole top of the fruit.

Bake the Skillet Strawberry-Rhubarb Crisp for about 20 minutes, until the topping is golden and the fruit filling is bubbling up like hot lava all around the edges.

Let cool for 15 minutes and serve with vanilla ice cream.