Using a sieve over a bow, sift together flour,baking powder, and salt, set aside.
Cream butter in another bowl using a hand mixer on high speed. until fluffy. About two minutes.
Separate eggs. Discard whites. Add sugar and egg yolks, mix until sugar is dissolved and mixture is light, about 4 minutes. With mixer on low speed, slowly add flour mixture, mix until dough just begins to come together,
about 1 minutes.
Turn dough onto a lightly floured surface, being it together with your hands. Divide dough in half and form 2 balls. Wrap each ball in plastic wrap, freeze for at least 30 minutes or up to 3 hours.
Arrange an oven rack in center of oven, heat to 350 F. Grease a 10" springform pan with butter. Remove a ball of dough from freezer, unwrap, and grate, using the large holes of a box grater. direcly into prepared pan.
Gently pat grated dough to even it out. Spread jam evenly over dough, leaving about a 1/2" border around edges. Grate remaining dough over jam layer, pat gently until surface is even. Bake until light golden brown, about
25-30 minutes. Let cool completely in pan, on a rack, before cutting into wedges.