Butter the bottom and sides of a 3.5 quart rectangular casserole slow cooker OR a 6 quart or larger oval slow cooker. Set aside.
In a large mixing bowl mix together the flour, sugar, cubed butter, baking soda, and baking powder. Using a mixer on the slow setting mix until the butter is cut into the dry ingredients and the mixture resembles coarse crumbs.
Mix in the eggs, one at a time.
Add the greek yogurt, apple sauce, vanilla and almond extracts and mix until you have a mixture that resembles a shaggy dough or stiff batter.
Using a rubber spatula scoop half of the batter into the prepared slow cooker and spread as evenly as possible.
Sprinkle the fresh raspberries evenly over the dough.
Spread the remaining dough over the top of the berries, being careful not to smash the berries too much.
Sprinkle the toasted almonds over the entire top of the top layer of dough.
Place a single layer of paper towels between the lid and the slow cooker. Cook on HIGH for 2 to 3 hours until a toothpick inserted in the middle of the coffee cake comes out clean.
Remove the lid and lift the stoneware insert from the heating element of the slow cooker and place the cake in the insert on a wire cooling rack and allow to cool completely.
Once cake is completely cooled, mix together the icing ingredients in a small bowl and drizzle the icing over the cake before serving.
If fresh raspberries are not in season you can use frozen berries or even raspberry jam instead!