diff --git a/core/src/builder/companion/src/expand/mod.rs b/core/src/builder/companion/src/expand/mod.rs
index 29ff9bd..3e9c489 100644
--- a/core/src/builder/companion/src/expand/mod.rs
+++ b/core/src/builder/companion/src/expand/mod.rs
@@ -120,9 +120,15 @@ pub fn expand(def: CompanionDef) -> SynResult<TokenStream> {
 					let collator = companion.#parachain_names.collator();
 
 					companion.#relay_chain_name.onboard_para(para, Box::new(collator)).map_err(|e| BuilderError::Relaychain(e.into())).map(|_| ())?;
-
 				)*
 
+				{
+					__hidden_tracing::enter_span!(sp_tracing::Level::TRACE, std::stringify!(#relay_chain_name - BlockBuilding:));
+
+					companion.#relay_chain_name.build_block().map_err(|e| BuilderError::Relaychain(e.into())).map(|_| ())?;
+					companion.#relay_chain_name.import_block().map_err(|e| BuilderError::Relaychain(e.into())).map(|_| ())?;
+				}
+
 				Ok(companion)
 			}