Raspberry Mazurkas

3 cups all-purpose flour
1 1/2 cups brown sugar
1 1/2 cups old-fashioned oats
1/2 cup walnuts - finely chopped
1 cup flaked coconut
1/2 tsp. salt
10 oz. melted, unsalted butter
About 18 oz raspberry jam or preserves

Preheat oven to 350F.
Grease 9x13 baking pan (one with sides like a sheet pan). Combine all ingredients, except butter and jam, in a large bowl.
Pour melted butter over the mixture and mix with hands until totally combined.
Press 1/2 mixture into bottom of pan (I roll with rolling pin to press real good).
Spread jam on top, leaving a 1/2 inch border around pan. Spread remaining crumb mixture on top and press lightly. Bake 25-30 minutes.
Cool before cutting.

Source of recipe: Mean Chef