Preheat oven to 375 degrees. Lightly grease an 8 x8-inch baking dish with unsalted butter or coconut oil and line it with unbleached parchment paper.
Prepare the base crust: pulse everything in food processor until you get moist crumbs. Press firmly into prepared pan to form a smooth even layer. If it’s too sticky, you can use some plastic wrap to help even it out. Refrigerate for 15 minutes.
In a small saucepan, heat the jam and the strawberries until the strawberries <g class="gr_ gr_63 gr-alert gr_spell gr_inline_cards gr_disable_anim_appear ContextualSpelling multiReplace" id="63" data-gr-id="63">loose</g> their shape. Mash lightly to blend in with the jam. Set aside.
Remove crust from refrigerator and bake until just firm in the center, 12-15 minutes.
Spread reserved strawberry mixture over warm crust.
Make <g class="gr_ gr_64 gr-alert gr_gramm gr_inline_cards gr_disable_anim_appear Punctuation only-del replaceWithoutSep" id="64" data-gr-id="64">crumble:</g> pulse coconut sugar, oat flour, baking powder, and butter in a food processor until moist crumbs form. Add the oats and the peanuts, and pulse 2-3 times more to chop them up a bit and so everything is combined. Crumble over the top of the bars and sprinkle with flaky sea salt.
Bake until filling is bubbly and crumble is golden brown, 25-30 minutes. Cool completely on a cooling rack before cutting. Refrigerate leftovers.